Suppose ABCD is a square. Let E be interior to the square such that EDC = ECD = 15°. What is the measure of angle EBC?

Point P is selected uniformly at random in the interior of square ABCD. What is the probability that angle APD is obtuse (greater than 90 degrees)?

A copy of square ABCD is rotated clockwise about vertex A to square A’B’C’D’ such that D’B’C is a straight line segment, as shown below. What is the measure of angle D’ED?

ABCD is a square and point P inside the square is such that PCD is an equilateral triangle. Find the angle α