Question

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

Answer 1

Answer:

$x^2 + y^2 = 16$

Step-by-step 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.

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