SOLUTION: a trench is 160ft long and 10ft deep, 8ft wide at the top and 5ft at the bottom. how many cubic ft of earth have been removed.

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Question 578158: a trench is 160ft long and 10ft deep, 8ft wide at the top and 5ft at the bottom. how many cubic ft of earth have been removed.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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a trench is 160ft long and 10ft deep, 8ft wide at the top and 5ft at the bottom.
how many cubic ft of earth have been removed.
;
The end is in the shape of a trapezoid, find it's area, multiply by the trench length.
:
A = h%2F2(a + b), where
h = 10' (deep)
a = 8'
b = 5'
:
A = 10%2F2(8 + 5)
A = 5(13)
A = 65 sq/ft
;
160 * 65 = 10,400 cu/ft of earth has been removed