cylinder: π/4 * (53.4^2 - (53.4-5)^2) * 750 cm^3 * 2.7 g/cm^3 * 1kg/1000g * $0.38/kg = $307.62
prism: (40-5)^2 * 750 cm^3 * 2.7 g/cm^3 * 1kg/1000g * $0.38/kg = $942.64
New streetlights will be installed along a section of the highway. The posts for the streetlights will
be 7.5 m tall and made of aluminum. The city can choose to buy the posts shaped like cylinders or
the posts shaped like rectangular prisms.
The cylindrical posts have a hollow core, with aluminum 2.5 cm thick, and an outer diameter of
53.4 cm. The rectangular-prism posts have a hollow core, with aluminum 2.5 cm thick, and a
square base that measures 40 cm on each side.
The density of aluminum is 2.7 g/cm3, and the cost of aluminum is $0.38 per kilogram.
a) What is the cost of the cylindrical posts, to the nearest cent?
b) What is the cost of the rectangular-prism posts, to the nearest cent?
1 answer
1 answer