Math Trivia : Find the area

There is a square of 10 cm one side. Find the area of ​​the shadow.

 

Answer

53 cm²

The area of ​​the shadow excluding the area of the rectangle of 2cm × 3cm in the center, is exactly half of the area excluding the area of the rectangle from that of the square.

In other words, if you take out central rectangle from the square, the four rectangles will remain and the area of the shadow is same to the area of four right triangle which are half of four rectangles respectively. 

Therefore, the area of ​​the shadow is (10 × 10 - 2 × 3) / 2 + 2 × 3 = 53 cm².

(Madison Square Garden)

 (Union Square)