Answer:

Explanation:
Here, ABCD is a square, and P is a point inside the square.
Where, Δ DPC is a equilateral triangle.
Therefore, DP=PC
Thus In triangles APD and BPC,
DP= CP
( because both are of 30°)
AD=CB ( sides of square)
Therefore by SAS postulate,
Δ APD≅Δ BPC