Geometry: Reflections

Greetings and welcome to Mathsux! Today we are going to go over reflections, one of the many types of transformations that come up in geometry.  And thankfully, it is one of the easiest transformation types to master, especially if you’re more of a visual learner/artistic type person. So let’s get to it!

What are Reflections?

Reflections on a coordinate plane are exactly what you think! When a point, a line segment, or a shape is reflected over a line it creates a mirror image.  Think the wings of a butterfly, a page being folded in half, or anywhere else where there is perfect symmetry.

Check out the Example below:

Screen Shot 2020-08-04 at 5.19.40 PM

Screen Shot 2020-08-04 at 4.57.07 PMScreen Shot 2020-08-04 at 4.57.34 PM.pngScreen Shot 2020-08-04 at 4.57.55 PMScreen Shot 2020-08-04 at 4.58.10 PM.pngScreen Shot 2020-08-04 at 4.59.19 PMScreen Shot 2020-08-04 at 4.59.36 PM.pngScreen Shot 2020-08-05 at 9.16.37 AM.png
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Practice Questions:

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Solutions:

Screen Shot 2020-08-04 at 5.15.37 PM.png

Still got questions?  No problem! Check out the video above or comment below! Happy calculating! 🙂

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Geometry: Intersecting Secant Theorem

Ahoy! Today we’re going to cover the Intersecting Secants Theorem!  If you forgot what a secant is in the first place, don’t worry because all it is a line that goes through a circle.  Not so scary right? I was never scared of lines that go through circles before, no reason to start now.

If you have any questions about anything here, don’t hesitate to comment below and check out my video for more of an explanation. Stay positive math peeps and happy calculating! 🙂

Wait, what are Secants?

Screen Shot 2020-07-14 at 10.07.54 PM

Intersecting Secants Theorem: When secants intersect an amazing thing happens! Their line segments are in proportion, meaning we can use something called the Intersecting Secants Theorem to find missing line segments.  Check it out below: 

Screen Shot 2020-07-14 at 10.44.53 PM

Let’s now see how we can apply the intersecting Secants Theorem to find missing length.

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Screen Shot 2020-07-14 at 10.10.23 PMScreen Shot 2020-07-14 at 10.10.39 PM.pngScreen Shot 2020-07-14 at 10.11.13 PMScreen Shot 2020-07-14 at 10.11.52 PM.pngScreen Shot 2020-07-14 at 10.13.24 PMScreen Shot 2020-07-14 at 10.13.57 PM.pngScreen Shot 2020-07-14 at 10.14.20 PM

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Ready to try the practice problems below on your own!?

Practice Questions: Find the value of the missing line segments x.

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Screen Shot 2020-07-20 at 9.30.01 AM

Solutions:

Screen Shot 2020-07-20 at 9.30.55 AM.png

Still got questions?  No problem! Check out the video above or comment below for any questions and follow for the latest MathSux posts. Happy calculating! 🙂

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To review a similar NYS Regents question check out this post here

Geometry: How to use SOH CAH TOA

Welcome back to Mathsux! This week, we’re going to go over how to find missing angles and side lengths of right triangles by using trigonometric ratios (sine, cosine, and tangent).  Woo hoo! These are the basics of right triangle trigonometry, and provides the basis for mastering so many more interesting things in trig! So, let’s get to it!

Also, if you have any questions about anything here, don’t hesitate to comment below. Happy calculating! 🙂

Trigonometric Ratios (more commonly known as Sine, Cosine, and Tangent) are ratios that naturally exist within a right triangle.  This means that the sides and angles of a right triangle are in proportion within itself.  It also means that if we are missing a side or an angle, based on what we’re given, we can probably find it!

Let’s take a look at what Sine, Cosine, and Tangent are all about!

Screen Shot 2020-07-04 at 5.03.29 PM.pngNow let’s see how we can apply trig ratios when there is a missing side or angle in a right triangle!Screen Shot 2020-07-04 at 5.04.02 PM

Screen Shot 2020-07-04 at 5.17.47 PMScreen Shot 2020-07-04 at 5.18.09 PM.pngScreen Shot 2020-07-04 at 5.15.19 PMScreen Shot 2020-07-04 at 5.15.54 PM.png

Now for another type of question; using trig functions to find missing angles, let’s take a look:Screen Shot 2020-07-04 at 5.05.01 PM.pngScreen Shot 2020-07-04 at 5.19.13 PMScreen Shot 2020-07-04 at 5.19.30 PM.png

Screen Shot 2020-07-04 at 5.19.51 PMScreen Shot 2020-07-04 at 5.05.38 PM.png

Try the following Practice Questions on your own!

Screen Shot 2020-07-04 at 5.05.55 PMSolutions:

Screen Shot 2020-07-04 at 5.06.37 PM.png

Still got questions?  No problem! Check out the video the same examples outlined above and happy calculating! 🙂

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Geometry: Perpendicular and Parallel Line Through a Given Point

Happy Wednesday math friends! Today we’re going to go over the difference between perpendicular and parallel lines. Then we’ll use our knowledge of equation of a line (y=mx+b) to see how to find perpendicular and parallel lines through a given point.  This is is a common question that comes up on the NYS Geometry Regents and is something we should prepare for, so let’s go!

If you need any further explanation, don’t hesitate to check out the Youtube video below that goes into detail on how to solve these types of questions one step at a time. Happy calculating! 🙂

Perpendicular lines: Lines that intersect to create a 90-degree angle and can look something like the graph below.  Their slopes are negative reciprocals of each other which means they are flipped and negated. See below for example!Screen Shot 2020-06-10 at 10.26.10 AM

Example: Find an equation of a line that passes through the point (1,3) and is perpendicular to line y=2x+1 .

Screen Shot 2020-06-10 at 10.28.20 AMScreen Shot 2020-06-10 at 10.27.43 AMScreen Shot 2020-06-10 at 10.28.42 AMScreen Shot 2020-06-10 at 10.29.06 AM

Parallel lines are lines that go in the same direction and have the same slope (but have different y-intercepts). Check out the example below!

Screen Shot 2020-06-10 at 10.29.26 AMExample: Find an equation of a line that goes through the point (-5,1) and is parallel to line y=4x+2.Screen Shot 2020-06-10 at 10.34.46 AMScreen Shot 2020-06-10 at 10.35.23 AMTry the following practice questions on your own!

Practice Questions:

1) Find an equation of a line that passes through the point (2,5) and is perpendicular to line y=2x+1.

 2) Find an equation of a line that goes through the point (-2,4) and is perpendicular to lineScreen Shot 2020-06-10 at 11.24.06 AM

 3)  Find an equation of a line that goes through the point (1,6) and is parallel to line y=3x+2.

4)  Find an equation of a line that goes through the point (-2,-2)  and is parallel to line y=2x+1.

Solutions:Screen Shot 2020-06-10 at 11.22.05 AM

Need more of an explanation? Check out the video that goes over these types of questions up on Youtube (video at top of post) and let me know if you have still any questions.

Happy Calculating! 🙂

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Geometry: Median of a Trapezoid Theorem

*If you haven’t done so, check out the video that goes over this exact problem, also please don’t forget to subscribe!

Medians of a Trapezoid copy

Screen Shot 2020-06-02 at 7.31.07 AMStep 1:  Let’s apply the Median of a Trapezoid Theorem to this question!  A little rusty?  No problem, check out the Theorem below.

Median of a Trapezoid Theorem: The median of a trapezoid is equal to the sum of both bases.Screen Shot 2020-06-02 at 7.32.31 AMStep 2: Now that we found the value of x , we can plug it back into the equation for Screen Shot 2020-06-02 at 7.33.44 AMmedian,  to find the value of median Screen Shot 2020-06-02 at 7.34.25 AM

Screen Shot 2020-06-02 at 7.34.48 AM

Want more practice?  Your wish is my command! Check out the practice problems below:

Practice Questions:

1.Screen Shot 2020-06-02 at 7.35.29 AMis the median of trapezoid ABCDEF, find the value of the median, given the following:Screen Shot 2020-06-02 at 7.35.47 AM2. Screen Shot 2020-06-02 at 9.01.08 AMis the median of trapezoid ACTIVE, find the value of the median, given the following:Screen Shot 2020-06-02 at 9.16.22 AM3.Screen Shot 2020-06-02 at 9.17.01 AMis the median of  trapezoid DRAGON, find the value of the median, given the following:Screen Shot 2020-06-02 at 9.22.13 AM

4. Screen Shot 2020-06-02 at 9.23.08 AMis the median of trapezoid MATRIX, find the value of the median, given the following:Screen Shot 2020-06-02 at 9.23.43 AM

Solutions:

Screen Shot 2020-06-02 at 9.25.05 AM

Need more of an explanation?  Check out the detailed video and practice problems. Happy calculating! 🙂

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Geometry: Area of a Sector

Youtube Area of a sector copy

Hi math friends, has anyone been cooking more during quarantine?  We all know there is more time for cookin’ and eatin’ cakes but have you ever been curious about the exact amount of cake you are actually eating?! Well, you’re in luck because today we are going to go over how to find the area of a piece of cake, otherwise known as the Area of a Sector!

Now, we’ll all be able to calculate just how much we are overdoing it on that pie! Hopefully, everyone is eating better than I am (I should really calm down on the cupcakes).  Ok, now to our question:

*Also, If you haven’t done so, check out the video that goes over this exact problem, and don’t forget to subscribe!

Screen Shot 2020-05-19 at 4.18.42 PMExplanation:

How do I answer this question? 

We must apply/adjust the formula for the area of a circle to find the area of the blue shaded region otherwise known as the sector of this circle.                                                    

How do we do this?    

Before we begin let’s review the formula for the area of a circle. Just a quick reminder of what each piece of the formula represents:

Screen Shot 2020-05-19 at 4.24.28 PMStep 1: Now let’s fill in our formula, we know the radius is 5, so let’s fill that in below:

Screen Shot 2020-05-19 at 4.26.08 PMStep 2: Ok, great! But wait, this is for a sector; We need only a piece of the circle, not the whole thing.  In other words, we need a fraction of the circle. How can we represent the area of the shaded region as a fraction?

Well, we can use the given central angle value, Screen Shot 2020-05-19 at 4.27.17 PM, and place it over the whole value of the circle,Screen Shot 2020-05-21 at 4.01.12 PM . Then multiply that by the area of the entire circle. This will give us the value we are looking for!

Screen Shot 2020-05-19 at 4.27.45 PMStep 3: Multiply and solve!Screen Shot 2020-05-19 at 4.28.38 PM

Ready for more? Try solving these next few examples on your own to truly master area of a sector!

Find the area of each shaded region given the central angle and radius for each circle:Screen Shot 2020-05-19 at 4.29.40 PM

Check the solutions below, when you’re ready:Screen Shot 2020-05-19 at 4.30.36 PMWhat do you think of finding the area of sector? Are you going to measure the area of your next slice of pizza?  Do you have any recipes to recommend?  Let me know in the comments and happy calculating! 🙂

 

Geometry: The Voluminous “Vessel” at Hudson Yards

Calling all NYC dwellers! Have you seen the new structure at Hudson Yards?  A staircase to nowhere, this bee-hive like structure is for the true adventurists at heart; Clearly, I had to check it out!

Where does math come in here you say?  Well, during my exploration, I had to wonder (as am sure most people do) what is the volume of this structure?  What do you think the volume of the Vessel is? (Hint: feel free to approximate!)

Screen Shot 2019-04-11 at 5.38.46 PM.png

Solution: I estimated the volume by using the formula of a three-dimensional cone. (Not an exact measurement of the Vessel, but close enough!) .

Screen Shot 2019-04-11 at 5.08.42 PM Screen Shot 2019-04-12 at 1.20.08 PM.pngWe can find the radius and height based on the given information above.  Everything we need for our formula is right here!

Screen Shot 2019-04-14 at 4.49.16 PM

Now that we have our information, let’s fill in our formula and calculate! Screen Shot 2019-04-11 at 5.14.58 PM.pngScreen Shot 2019-04-11 at 5.17.30 PM.png

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Extra Tip! Notice that we labeled the solution with feet cubed Screen Shot 2019-04-14 at 4.53.49 PM.png, which is the short-handed way to write “feet cubed.”  Why feet cubed instead of feet squared? Or just plain old feet? When we use our formula we are multiplying three numbers all measured in feet:

radius X radius X (Height/3)

All three values are measured in feet! –> Feet cubed (Screen Shot 2019-04-14 at 4.53.49 PM.png)

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Did you get the same answer? Did you use a different method or have any questions?  Let me know in the comments and happy mathing! 🙂

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Geometry: Intersecting Secants

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*Extra Tip! Why does this formula work in the first place!??  If we draw lines creating and proving triangle RTQ and triangle RPS are similar by AA, this leads us to know that the two triangles have proportionate sides and can follow our formula!         ___________________________________________________________________________________

Still got questions?  Let me know in the comments and remeber having questions is a  good thing!

Also, happy holidays from Mathsux! May your December break be filled with family, food, happiness, and maybe some math problems! 🙂

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The Magic of the “Golden Ratio”

Walking around NYC, I was on a mission to connect mathematics to the real world.  This, of course, led me to go on a mathematical scavenger hunt in search of  the “Golden Ratio.” Hidden in plain sight, this often times naturally occurring ratio is seen everywhere from historic and modern architecture to nature itself. 

What is this all-encompassing “Golden Ratio” you may ask?
It’s a proportion, related to a never-ending sequence of numbers called the Fibonacci sequence, and is considered to be the most pleasing ratio to the human eye.  The ratio itself is an irrational number equal to 1.618……..(etc.).

Why should you care?
When the same ratio is seen in the Parthenon, the Taj Mahal, the Mona Lisa and on the shores of a beach in a seashell, you know it must be something special!
Screen Shot 2018-11-19 at 10.48.04 PM.png Screen Shot 2018-11-19 at 10.48.34 PM.png Screen Shot 2018-11-19 at 10.49.10 PM Screen Shot 2018-11-19 at 11.07.21 PM

Random as it may seem, this proportion stems from the following sequence of numbers, known as the Fibonacci sequence:

1, 1, 2, 3, 5, 8, 13, 21, …….

Do you notice what pattern these numbers form?
Capture(Answer: Each previous two numbers are added together to find the next number.)

The Golden RectangleThe most common example of the “Golden Ratio” can be seen in the Golden rectangle.  The lengths of this rectangle are in the proportion from 1: 1.618 following the golden ratio. Behold the beauty of the Golden Rectangle:

Screen Shot 2018-11-18 at 5.58.24 PM

How is the Fibonacci Sequence related to the Golden Ratio?                                               What if we drew a golden rectangle within our rectangle?

Screen Shot 2018-11-18 at 5.58.13 PM.png

Then drew another golden rectangle within that golden rectangle?

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And we kept doing this until we could no longer see what we were doing…….

Screen Shot 2018-11-19 at 8.38.34 AM

The proportion between the width and height of these rectangles is 1.618 and can also be shown as the proportion between any two numbers in the Fibonacci sequence as the sequence approaches infinity. Notice that the area of each rectangle in the Fibonacci sequence is represented below in increasing size:Screen Shot 2018-11-19 at 10.31.51 PM

Where exactly can you find this Golden Ratio in real life? Found in NYC! The Golden ratio was seen here at the United Nations Secretariat building in the form of a golden rectangle(s).  Check it out!

Golden Ratio Pic

Where have you seen this proportion of magical magnitude?  Look for it in your own city or town and let me know what you find! Happy Golden Ratio hunting! 🙂

If you’re interested in learning more about the golden ratio and are also a big Disney fan, I highly recommend you check out Donald Duck’s Math Magic!

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