High School Math : Circles

Study concepts, example questions & explanations for High School Math

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Example Questions

Example Question #1 : Pre Calculus

What is the center and radius of the circle indicated by the equation?

\(\displaystyle (x-2)^2+y^2=36\)

Possible Answers:

\(\displaystyle (2,0),\ r=6\)

\(\displaystyle (-2,0),\ r=6\)

\(\displaystyle (2,0),\ r=36\)

\(\displaystyle (-2,0),\ r=36\)

Correct answer:

\(\displaystyle (2,0),\ r=6\)

Explanation:

A circle is defined by an equation in the format \(\displaystyle (x-h)^2+(y-k)^2=r^2\).

The center is indicated by the point \(\displaystyle (h,k)\) and the radius \(\displaystyle r\).

In the equation \(\displaystyle (x-2)^2+(y)^2=36=6^2\), the center is \(\displaystyle (2,0)\) and the radius is \(\displaystyle 6\).

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