The area of the bottom blank trapezoid is: (3+8)×(6+8)÷2=77 cm?

The area of the blank triangle above is: 3x8 ÷ 2 = 12cm?

∴ The shaded area is:100-77-12 =11cm?

2. The height of the trapezoid is: 37-8- 10- 13 = 6cm.

The area of the trapezoid is: (8+ 13) × 6 ÷ 2 = 63cm?

The area of the blank triangle is: 6× 13÷2=39 cm?

∴ The area of the shaded part is: 63-39 = 24cm?