convert from rectangular coordinates to polar coordinates x=y

Answer 1

x/r = cosØ ---> x = rcosØ
y/r = sinØ ---> y = rsinØ

rcosØ = rsinØ
sinØ/cosØ = 1
tanØ = 1
Ø = π/2

which makes sense to me,
x = y is a straight line with (0,0) as the intercept and a 45° angle
Ø = 45° is the correct angle of our line, since no restriction is placed on r, r can be any length, so it is the same straight line

Answer 2

thank you