Question

A sign made od soild wood is in the shape of a pyramid. The base is a triangle with a base of 6 feet and a height of 4 feet. The height of the sign is 7 feet. The wood costs $3 per cubic foot. What is the cost of the sign?A. $28B. $56C. $84D. $168

Answer 1

The volume of a pyramid can be calculated using the next formula

$A=\frac{1}{3}(B\times h)$

where B is the area of the base

$B=\frac{\text{base x heigth}}{2}=\frac{6\times4}{2}=\frac{24}{2}=12ft^2$$h=7$

we substitute the values

$V=\frac{1}{3}(12\cdot7)=28ft^3$

then we will calculate the cost

1 cubic foot--- $3

28 cubic feet --- x

$x=28\cdot3=84$

the cost of the sign is $84