math
posted by Willy on .
The concrete for a sidewalk is being poured outside the perimeter of a new subdivision, which is a 280 ft. by 720 ft. rectangle. The building code requires that the sidewalk be 5 feet wide and 8 inches deep. How many cubic yards of concrete will need to be poured? How much will the concrete for the new subdivision cost if the price per cubic yard of concrete is $74.50 and an extra 5% of concrete is being ordered?

Dimensions of the rectangle including the sidewalk is
290 by 730 , (added 5 feet on each side)
surface area of sidwwalk
= 290x730  280x720
=10100 ft^2
volume of sidwwalk
= 10100(8/12) ft^3
= 20200/3 ft^3
but we are ordering 5% extra
volume ordered
= 20200/3 (1.05)
= 7070 cubic ft
= 7070/27 cubic yards
= 261.85 cubic yards
BUT we will probably have to order 262 yds^3
for a cost of
262(74.50)
= $19,519.00 
$19,519.00

$1

$19,519.000

19,000,000,00000,000EWAHGQHGO[V