Answer:
see explanation
Step-by-step explanation:
the area (A) of a trpezoid is calculated as
A = [tex]\frac{1}{2}[/tex] h (b₁ + b₂ )
b₁, b₂ are the parallel bases and h the perpendicular height between them
(1)
b₁ = 12, b₂ = 8 , h = 5
A = [tex]\frac{1}{2}[/tex] × 5 × (12 + 8) = 2.5 × 20 = 50 cm²
(2)
b₁ = 6 , b₂ = 4 , h = 3
A = [tex]\frac{1}{2}[/tex] × 3 × (6 + 4) = 1.5 × 10 = 15 cm²
(3)
b₁ = 7 , b₂ = 4 , h = 4
A = [tex]\frac{1}{2}[/tex] × 4 × (7 + 4) = 2 × 11 = 22 cm²
