Equation of A Circle: Geometry

Equation of A Circle

Ahoy math friends and welcome to Math Sux! In this post, we are going to learn about the equation of a circle, mainly how to write it when given a circle on a coordinate plane. We’ll see how to find the radius and center from the graphed circle and then see how to transfer that into our equation of a circle. And we’re going to do all of this step by step with the following Regents question. Stay curious and happy calculating! 🙂

Equation of A Circle

How do I Answer this Question?

Let’s mark up this coordinate plane and take as much information away from it as possible. When looking at this coordinate plane, we can find the value of the circle’s center and the circle’s radius.

Equation of A Circle

Now that found the center and radius, we can fit each into our equation:

Center=(-3,-4)

Radius=5

The only equation that matches our center and radius, is choice (2).

Screen Shot 2016-06-29 at 11.16.29 AM

If the above answer makes sense to you, that’s great! If you need a little further explanation, keep going!

Equation of a Circle:

Equation of a Circle: Let’s take a look at our answer and break down what each part means:

Equation of A Circle

So what do you think of circles now?  Not to shabby, ehh?  🙂

Looking for more on circles?  Check out this post on how to find the Area of a Sector here!

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Recursive Formula: Algebra

Howdy math peeps! In this post, we are going to go over the recursive formula step by step by reviewing a Regent’s question. Yes, it is the recursive formula jam, well at least it’s my kind of jam.  These things may look weird, confusing, and like a “what am I doing?” moment, but trust me they are no so bad!

How do I answer this question?

At first glance, all of these answer choices may look exactly the same. The first thing I would want to do with this question is to identify how all of theses answer choices are different. Take a look below:

What is the Recursive Formula?

A Recursive Formula is a formula that forms a sequence based on the previous term value. All this means is that it uses a formula to form a sequence-based pattern.

Let’s go through each choice to identify the answer:

Our goal is to test out each choice given, until we get the desired sequence:

What is the recursive formula
What is the recursive formula
What is the recursive formula

Still have questions about recursive formulas? Check out more on recursive formulas here!

Still got questions? No problem! Check out the video above for more or try the NYS Regents question below, and please don’t hesitate to comment with any questions. Happy calculating! 🙂

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