Convert the following rectangular coordinates to polar coordinates?

using (r, θ)

the reference angle for all the points is π/4 (aka 45°)

you have the 45-45-90 reference triangle which has a side ration of 1:1:√2

so for all 4 points r = 3√2

(3,3) is in Quadrant I so θ = reference angle

=> (3,3) = (3√2, π/4)

(-3,3) is in Quadrant II so θ = π − reference angle

=> (-3,3) = (3√2, 3π/4)

(-3,-3) is in Quadrant III so θ = π + reference angle

=> (-3,-3) = (3√2, 5π/4)

(3,-3) is in Quadrant IV so θ = 2π − reference angle

=> (3,-3) = (3√2, 7π/4)

(3*sqrt(2), 45°), (3*sqrt(2), 135°), (3*sqrt(2), 315°), (3*sqrt(2), 225°)

The last two could also be written with negative angles (measuring clockwise): (3*sqrt(2), -45°), (3*sqrt(2), -135°)

If you want radians: 45° = pi/4, 135° = 3pi/4, 315° = 7pi/4, and 225° = 5pi/4

(3, 3) = (3√2, pi/4)

(-3, 3) = (3√2, 3pi/4)

(3, -3) = (3√2, 7pi/4)

(-3, -3) = (3√2, 5pi/4)