Answer:
- 256 ft^2
- 50 ft^2
- 25 ft^2
- 281 ft^2
Explanation:
Prism Area
The total surface area of a rectangular prism is given by ...
SA = 2(LW +H(L +W))
For L = 12 ft, W = 5 ft, H = 4 ft, the surface area is ...
SA = 2((12 ft)(5 ft) +(4 ft)(12 ft +5 ft)) = 2(60 ft^2 +(4 ft)(17 ft))
= 2(60 ft^2 +68 ft^2) = 256 ft^2 . . . blank 1
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Pyramid Lateral Area
The lateral area of the pyramid is 4 times the area of one triangular face:
LA = 4(1/2)bh = 2(5 ft)(5 ft) = 50 ft^2 . . . blank 2
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Pyramid Base Area
The area of the square base of the pyramid is the square of the length of one edge:
B = (5 ft)^2 = 25 ft^2 . . . blank 3
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Total Exposed Area
The exposed area of the prism is its area less that of the base of the pyramid. The total exposed area is the sum of prism exposed area and lateral area of the pyramid.
total exposed area = (exposed prism area) + (pyramid lateral area)
= (prism area) - (pyramid base area) + (pyramid lateral area)
= 256 ft^2 - 25 ft^2 + 50 ft^2
total exposed area = 281 ft^2 . . . blank 4