Question

What is the equation of a circle centered at the origin with radius 20?

A. x3 + y3 = 400
B. x3 + y3 = 20
C. x2 + y2 = 20
D. x2 + y2 = 400

Answer 1

Answer:d

Explanation:

Answer 2

we know that
the equation of a circle is
(x-h)²+(y-k)²=r²
where
(h,k)-----> is the center
r--------> is the radius

is the center is the point (0,0) and radius r=20
then
(h,k) is (0,0)

(x-0)²+(y-0)²=20²---------> (x)²+(y)²=400


the answer is
the option D.) x2 + y2 = 400