1. The area of shadow is equal to the area of rectangle minus the area of triangle AFC minus the area of triangle DBF plus the area of EFGH.

The sum of the bottoms of these two triangles is the length of BC and the height is the same height AB.

Therefore, S Yin = BC * AB/2+36 =12 * 20/2+36 =156 (square centimeter).

2. The area of quadrilateral ABCD = 16*20=320 (square centimeter)

The area of the triangle DMC = 16* 10/2=80 (square centimeter).

The area of triangle APD = 320-120-80 =120 (square centimeter).

AP= 120*2/20= 12 (cm)

PB= 16- 12=4 (cm)

The area of the triangle PBM =4* 10/2=20 (square centimeter).

The area of the triangle PMD = 120-20= 100 (square centimeter).