The shadow of the first figure is a circle, which can be calculated by the formula of circle area. Namely: (10×10-4× 4 )× 3.14 = 263.76cm2:

The second figure is the area of a semicircle plus a triangle. The radius of semicircle = 16÷2=8dm, and the area of semicircle = 8× 8× 3.14 ÷ 2 =100.48 cm2; The area of triangle = 16×8÷2=64 square centimeters; The area of the whole shadow =100.48+64 =164.48cm2.