Question 159142
    How many washers can be made from a cube of metal 4 inches on a side if the washers are 5/8 inch in diameter and 1/6 inch thick?The hole in the center of the washers is 1/4 inch in diameter.
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The answer can be found by:
"volume of cube" divided by "volume of a single washer"
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First, volume of cube:
Since it's a cube, all sides are equal so
height * width * length
4*4*4 = 64 cubic inches
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Second, volume of washer:
"volume of entire disc" - "volume of center hole"
Let's calculate:
"volume of entire disc" = "area of circle" * thickness
(pi)r^2 * thickness
(3.14)(5/8)^2 * (1/6)
(3.14)(25/64)(1/6)
(3.14)(0.390625)(1/6)
0.204
"volume of center hole"
(pi)r^2 * thickness
(3.14)(1/4)^2 * (1/6)
(3.14)(1/16) * (1/6)
(3.14)(1/96)
0.033
"volume of washer" then is:
0.204-0.033 = 0.171 cubic inches
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Conclusion:
"volume of cube" divided by "volume of a single washer"
64/0.171 = 374 (number of washers from the cube)