Question

The circle is centered at the origin, and the length of its radius is 5 what is the equation of the circle ?

Answer 1

Choice A is the answer.

Explanation:

We have given a graph of circle.

Radius = r = 5 units

From graph , we observed that center of graph is (0,0).

(h,k) = (0,0)

(x-h)²+(y-k)² = r² where (h,k) is center and r is radius of circle.

Putting given values , we have

(x-0)²+(y-0)² = (5)²

x²+y² = 5² is equation of circle with radius 5.

Answer 2

x² + y² = 5²

Explanation:

The equation of a circle is given in the form;

(x-a)² + (y-b)² = r²

Where, (a,b) is the center of the circle and r is the radius of the circle;

In this case; the center is (0,0) and r is 5 units

Therefore;

The equation of a circle will be;

(x-0)² + (y-0)² = 5²

Giving us;

x² + y² = 5²