Answer:
Step-by-step explanation:
the shape is a square (meaning all sides are equal)
CR = AR = CA=AT=AR=AT=RT=RS=ST=CS=4
the triangle in a square is an equilateral triangle meaning all sides are equal
the sum of angles in a triangle is 180°
all the angles in each triangle is 180/3 = 60°
the sum of angles in a square is 360
the angles at each angles ∠A =∠T=∠S= ∠C = 360/4 = 90°
