Answer:
see below
Step-by-step explanation:
surface area = 2 (LW + LH + WH)
a)
where L = length = 8
W = width = 2
H = height = 2
plugin values into the formula:
surface area = 2 (8*2 + 8*2 + 2*2)
= 2 (16 + 16 + 4)
= 72
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b)
where L = length = 2
W = width = 3
H = height = 9
plugin values into the formula:
surface area = 2 (2*3 + 2*9 + 3*9)
= 2 (6 + 18 + 27)
= 102
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c)
surface area = 2(area of rectangular side) + 2(area of triangular side) + base area
plugin values into the formula:
surface area = 2 (2*7) + 2( 1/2 * 7 * 6.1) + (2*7)
= 28 + 42.7 + 14
= 84.7
