Figure (1):12×12 ÷ 2 = 72 (square centimeter);

Figure (2): DE = 14- 12 = 2 (cm),

DF= 122？ 22=235 (cm),

12×235÷2= 1235 (square centimeter);

Figure (3): Be = 18- 12 = 6 (cm),

DF= 122？ 62=63 (cm),

12×63÷2=363 (square centimeter