Problem 23
Triangles: A = bh/2
A = (6)(4)/2 = 24/2
12 ft²
Rectangles: A = bh
A = (8)(5)
40 ft²
Total SA = 2 triangles + 3 rectangles
Total SA = (2 · 12) + (3 · 40)
Total SA = 24 + 120 = 144 ft²
Problem 24
0.07(total) = $9.45
total = 9.45 ÷ 0.07
total = $135
Problem 12
Trapezoid: A = (a + b) · h/2
A = [(9 + 21) · 12]/2
A = (30·12)/2 = 360/2
180 ft²
Triangle: A = bh/2
A = (8)(21)/2 = 168/2
84 ft²
Total area: 180 + 84 = 264 ft²
Hope this helps and God bless!
