Question

Identify the radius and the center of a circle whose equation is (x - 5)2 + y2 = 81.

The radius of the circle is
The center of the circle is at (1
units.

Answer 1

The center is (5,0) and r=9.

Explanation:

The standard form of a circle is
`(x-h)^2+(y-k)^2` where (h,k) is the center and r is the radius.

On comparing your equation of

`(x - 5)^2 + (y-0)^2 = 9^2`, we should see that h=5,k=0, and r=9.

The center is (5,0) and r=9.

Answer 2

The center is at (5,0) and the radius is 9

Explanation:

(x - 5)^2 + y^2 = 81.

An equation for a circle can be written in the form

(x-h)^2 + (y-k)^2 = r^2

Where (h,k) is the center and r is the radius

Rewriting the equation

(x - 5)^2 + y^2 = 81.

(x - 5)^2 + (y-0)^2 = 9^2

The center is at (5,0) and the radius is 9