Question

What is the equation of a circle whose center is at the origin and whose radius is 9?

Answer 1

The possible answers;

x2 + y2 = 3
x2 + y2 = 9
x2 + y2 = 81

Answer 2

equation of a circle whose center is at the origin and whose radius is r, will be
\(\large x^2+y^2=r^2\)
here, just plug in r=radius = 9

Answer 3

81?

Answer 4

yes.

Answer 5

Thank you!

Answer 6

welcome ^_^