Point P lies inside square ABCD such that triangle ABP is equilateral. Find (angle) PCD in degrees.

Hints:

Let the length of sides be 2 units.

Let E be the midpoint of DC

and

Let F be the midpoint of AB

Find PF

Find PE

Use trig to find angle C in triangle  CEP

Please let guest do it from here.

hint :    triangle BPC is an isosceles triangle