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! 🙂

 

Algebra 2: Solving Radical Equations

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Today we’re back with Algebra 2, this time solving for radical equations!  Did you say “Radical Equations?” As in wild and crazy equations? No, not exactly, radicals in math are used to take the square root, cubed root, or whatever root of a number.

Radicals are actually pretty cool because we can write them a couple of different ways and they all mean the same thing! Check it out below:Screen Shot 2020-05-12 at 11.23.20 AM.pngStill not sure of their coolness? Let’s see what they look like with actual numbers:
Screen Shot 2020-05-12 at 11.24.21 AM.pngExample: Solve the following algebraic equation below for the missing variable (aka, solve for x).Screen Shot 2020-05-12 at 11.25.03 AM.pngExplanation:

How do I answer this question?   

The question wants us to solve for x using our knowledge of radicals and algebra. You can also check out how to solve this question on Youtube here!

How do we do this? 

Step 1: We start solving this radical equation like any other algebraic problem: by getting x alone. We can do this easily by subtracting 7 and then dividing out 5.Screen Shot 2020-05-12 at 11.26.21 AM.pngStep 2: Now, to get rid of that pesky radical, we need to square the entire radical.  Remember, whatever we do to one side of the equation, we must also do to the other side of the equation, therefore, we also square 14 on the other side of the equal sign. 

*This gets rid of our radical and allows us to solve for x algebraically as normal!Screen Shot 2020-05-12 at 11.29.11 AM.pngScreen Shot 2020-05-12 at 11.29.34 AM.pngWhat happens when there is a cubed root though!?!? When dividing polynomials with different value roots, raise the entire radical to that same power of root to cancel it out:Screen Shot 2020-05-12 at 11.30.21 AM.pngRemember, we know radicals can also be written as fractions: Screen Shot 2020-05-12 at 11.31.01 AM.pngTherefore we also know that if we raise the entire radical expression to the same power of the root, the two exponents will cancel each other out:Screen Shot 2020-05-12 at 11.31.47 AM.pngWant more practice? Try solving these next few examples on your own. Screen Shot 2020-05-12 at 11.32.39 AM.pngWhen you’re ready, check out the below:Screen Shot 2020-05-12 at 11.33.12 AM.png

Did I miss anything?  Don’t let any questions go unchecked and let me know in the comments! Happy calculating! 🙂 

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Algebra 2: Dividing Polynomials

Screen Shot 2020-05-03 at 11.43.01 AMNow that everyone is home, there is no better time to go over dividing polynomials! Whether school is out or not, dividing polynomials will always come in handy… I think.

Either way at some point, you may need to know how to answer these types of questions. The cool thing about dividing polynomials is that it’s the same long division you did way back in grade school (except now with a lot of x). Ok, let’s get to it and check out the question below:

Also, if you haven’t done so, check out the video related that corresponds to this problem on Youtube! 🙂

Screen Shot 2020-05-04 at 10.21.17 PMExplanation:

How do I answer this question?

The question wants us to divide polynomials by using long division.

How do we do this?     

Step 1: First we set up a good ole’ division problem with the divisor, dividend, and quotient to solve.Screen Shot 2020-05-04 at 10.43.48 PM.pngStep 2: Now we use long division like we used to back in the day! If you have any confusion about this please check out the video in this post.Screen Shot 2020-05-04 at 10.22.52 PMScreen Shot 2020-05-04 at 10.23.27 PM.pngWhat happens when there is a remainder though!?!? When dividing polynomials with a remainder in the quotient, the answer is found and checked in a very similar way! Check it out below:
Screen Shot 2020-05-04 at 10.23.44 PM

Screen Shot 2020-05-04 at 10.24.06 PM

Notice we represented the remainder by adding Screen Shot 2020-05-04 at 10.35.06 PM to our quotient! We just put the remainder over the divisor to represent this extra bit of solution.

Want more practice? Try solving these next few examples on your own. Screen Shot 2020-05-04 at 10.45.10 PM.pngWhen you’re ready, check out the solutions below:Screen Shot 2020-05-04 at 10.45.37 PMI hope everyone is finding something fun to do with all this extra time home! That can include everything from baking a cake to studying more math of course, happy calculating! 🙂 

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Earth Day Fractals!

In honor of Earth Day last week, I thought we’d take a look at some math that appears magically in nature.  Math? In nature?  For those of you who think math is unnatural or just terrible in general, this is a great time to be proven otherwise!

The key that links math to nature is all about PATTERNS. All math is based on is patterns.  This includes all types of math, from sequences to finding x, each mathematical procedure follows some type of pattern. Meanwhile back in the nearest forest, patterns are occurring everywhere in nature.

The rock star of all patterns would have to be FRACTALS. A Fractal is a repeating pattern that is ongoing and has different sizes of the exact same thing!  And the amazing thing is that we can actually find fractals in our neighbor’s local garden.

Let’s look at some Fractal Examples:

(1) Romanesco Broccoli:  Check out those repeating shapes, that have the same repeating shapes on those shapes and the same repeating shapes on even smaller shapes and…. my brain hurts!

Screen Shot 2020-04-26 at 10.18.47 PM                                                          Screen Shot 2020-04-30 at 10.15.34 PM

(2) Fern Leaves:  The largest part of this fractal is the entire fern leaf itself.  The next smaller and identical part is each individual “leaf” along the stem.  If you look closely, the pattern continues!

Screen Shot 2020-04-26 at 10.30.02 PM                                                        Screen Shot 2020-04-30 at 10.16.13 PM

(3) Leaves:  If you’ve ever gotten up real close to any type of leaf, you may have noticed the forever repeating pattern that gets smaller and smaller. Behold the power and fractal pattern of this mighty leaf below!

Screen Shot 2020-04-27 at 3.45.36 PM.                                                        Screen Shot 2020-04-30 at 10.16.55 PM

Just in case fractals are still a bit hard to grasp, check out the most famous Fractal below,  otherwise known as Sierpinski’s Triangle.  This example might not be found in your local back yard, but it’s the best way to see what a fractal truly is up close and infinite and stuff.

sierpinski.gif Screen Shot 2020-04-30 at 10.19.21 PM

Looking for more math in nature?  Check out this post on the Golden Ratio and happy calculating! 🙂

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COVID-19: What does #FlattenTheCurve even mean?

If you are a human on Earth, then I’m sure you’ve heard about the coronavirus and are currently social distancing. Here in NYC, I’m quarantining like everyone else and listening to all the beautiful math language that has suddenly become mainstream (so, exciting)!  #FlattenTheCurve has become NY’s new catchphrase and for anyone confused about what that means, you’ve come to the right place!

The coronavirus spreads at an Exponential Rate, which means it spreads in a way that increases faster and faster every day.

What does this mean?

For Example, one person with the virus can easily spread the virus to 5 other people, those 5 people can then spread the virus to another 5 people each for a total of an extra 25 people, these 25 people can then spread it to another 5 people each for an extra 125 infected people! And the pattern continues……. See below to get a clearer picture:

Screen Shot 2020-04-12 at 1.26.39 PMScreen Shot 2020-04-12 at 1.20.22 PM.   *Note: These numbers are not based on actual coronavirus data

The Example we just went over is equal to the exponential equation Screen Shot 2020-04-12 at 1.21.48 PM, but it is only that, an Example! The exact pattern and exponential equation of the future progress of the virus is unknown! We mathematicians, can only measure what has already occurred and prepare/model for the future.  To make the virus spread less rapidly, it is our duty to stay home to slow the rate of this exponentially spreading virus as much as possible.

We want to #FlattenTheCurve a.k.a flatten the increasing exponential curve of new coronavirus cases that appear every day! Hopefully, this post brings some clarity to what’s going on in the world right now.  Even with mathematics, the true outcome of the virus may be unknown, but understanding why we are all at home in the first place and the positive impact it has is also important (and kind of cool).

Stay safe math friends and happy mathing! 🙂

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Bored and Confused?

Calling all students, teachers, and parents!  As everyone is stuck at home during a global pandemic, now is a great time we are all forced to try and understand math (and our sanity level) a little bit more.  Well, I may not be able to help you with the keeping sanity stuff, but as far as math goes, hopefully, the below websites offer some much needed mathematic support.

All jokes aside I hope everyone is staying safe and successfully social distancing.  Stay well, math friends! 🙂

Kahn Academy: The same Kahn Academy we know and love still has amazing videos and tutorials as usual, but now they also have a live “homeroom” chat on Facebook LIVE every day at 12:00pm. The chats occur daily with Kahn Academy founder Sal and at times feature famous guests such as Bill Gates. Click the link below for more:

Khan Academy Homeroom Screen Shot 2020-04-04 at 12.21.20 PM

 

Study.com: In a time when companies are being more generous, Study.com is here for us as they offer up to 1000 licenses for school districts and free lessons for teachers, students, and parents.  Check out all the education freebies here:

Study.com

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Math PlanetIf you’re looking for free math resources in Pre-Algebra, Algebra, Algebra 2, and Geometry then you will find the answers you need at Math Planet.  All free all the time, find their website here:

MathPlanet 

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JMAP: For anyone who has to take the NYS Regents at some point (whenever we’re allowed to go outside again), JMAP has every old Regents exam as well as answers to boot! Did I mention each exam is free and printable?  Find their website here:

JMAP

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What is your favorite educational site?  Let me know in the comments, and stay well! 🙂