Question

A circle has center O(5, −1) and radius 5. Which of the following points is on the circle?

V(2, 3)
X(−3, −2)
Y(5, −4)
Z(6, 9)

Answer 1

The correct answer is the first one listed.

Explanation:

First you have to determine what the equation for that circle is. The standard form of a circle is

`(x-h)^2+(y-k)^2=r^2` where h and k are the coordinates of the center and the radius is squared. Using the given info, our equation will look like this:

`(x-5)^2+(y+1)^2=25`

Now we use the coordinates given and plug in 2 for x and 3 for y and do the math and see if the 2 sides are equal.

`(2-5)^2+(3+1)^2=25`

and 9 + 16 = 25, right? So that's how you can check the other coordinate pairs to verify that they DON'T work out!