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39. Alain works for a company that
built a goldfish pond for a local university. He has to plaster
the interior sides of the pond, which is shaped like a rectangular prism
with the dimensions
shown in the picture below.
a. What is the volume, in cubic feet, of the goldfish pond? Show or explain your work.
b. What is the total surface area of
the interior sides and bottom of the pond? Show or
explain your work.
c. If the company charges $1.50 per
square foot to plaster the pond, what will it cost to
plaster the 4 interior sides and the bottom of the pond?
link to answer for test item 39
a. for this your reference sheet comes in handy. The formula for the
volume of a rectangular prism is listed as
v=Bh ( the capital B means the area of the base) so v=
length times width times height
you'll want your calculator too.
first list the dimensions of the
goldfish pond
l = 30 feet
w = 20 feet
h = 4 feet
then multiply using your calculator
2400 cubic feet is the answer to the
volume
b. The reference sheet does not have a surface area formula but you need the area of each surface( ya! that's what surface area is!)
The goldfish pond has a bottom, 4 interior sides and no top. That's 5 surfaces to find the area of and then add together.
bottom A=lw= 30 times 20 =600
two short sides A=lw= 20 times 4 = 80 so two of them is 160
two longer sides A= lw= 30 times 4 = 120 so two of them is 240
600 +160 + 240 =1000 square feet
c If the company charges $1.50
per square foot to plaster the pond, what will it cost to
plaster the 4 interior sides and the bottom of the pond?
from part b I know there are 1000 square feet if each square foot cost $1.50 is 1000 times $1.50 or $1500