Point (r,θ)=(1.5,0.75π).
send to (1.5,0.75π),
Purple point ,is at ( 1.5 , (5π /6 )+1/3 )
Then
0.75π = (3/4)π
Now Drag purple point to (1.5, (3/4)π )
Substract (5π/6 ) + 1/3 - (3/4) π = (5/6 - 3/4)•π + 1/3
. = (20-18)/24 π + 1/3
. = π/12 + 1/3
Then answer is
Point will be at same x distance 1.5
and will be at y distance = π/12 + 1/3 , from purple point