Question

Write the equation for the circle with center at (0,0) and radius of 4.

Answer 1

(x)^2 + (y)^2 = 16

Answer 2

`x^2 + y^2 = 16`

Explanation:

The center of a circle can be used to write the equation
`(x-h)^2 + (y-k)^2 = r^2`. Notice h and k are the opposite value as in the equation.

Since the center is (0,0), substitute h=0 and k=0. Then substitute r = 4.

`(x-0)^2+(y-0)^2 = 4^2\\x^2 + y^2 = 16`