Question

Convert the rectangular equation to polar form x^2+y^2=9

Answer 1

Polar form is (r,θ) where r is the radius and tan θ = x/y

The equation you provided is a circle so 9 = r² →  r = 3

tan θ = 1/1
tan θ = 1
$tan^{-1}$ (tan θ) = $tan^{-1}$ (1)
     θ = 45°

Answer: (3, 45°)  or (3, $\frac{ \pi}{4}$)