Apoint in polar coordinates is given. convert the point to rectangular coordinates.
(0,pi)
(x, y) = ( , )

X=rcosθ
y=rsinθ

x=0cos(π)
y=0sin(π) 

x=0
y=0

(0, 0)

Or technically, common sense:

r is equal to 0, so it is located at the origin, which is (0, 0) in rectangular coords.