Lesson 18
Volume of Cylinders
Find the area of each circle. Use 3.14 for .
1.
2.
3.
What will have more area, a square with sides that are
10 units or a circle with a diameter of 10 units?
Target:
Calculate the volume of cylinders.
The volume of a cylinder is equal to the product
of the area of the base (B) and the height (h).
V = Bh
V=
2
πr h
Find the volume of the cylinder.
Use 3.14 for π.
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Write the formula.
Substitute known values.
Find the value of the power.
Multiply.
V = πr2h
V ≈ (3.14)(8)2(5)
V ≈ (3.14)(64)(5)
V ≈ 1004.8
The volume of the cylinder is about 1,004.8 cubic
meters.
A silo is filled with corn to the top of the cylindrical part.
The cylindrical part of the silo is 90 feet tall and has a diameter
of 15 feet. About how many cubic feet of corn does the silo
hold?

Find the length of the radius.
Write the formula.
Substitute known values.
Find the value of the power.
Multiply.
Round the answer.

The silo holds about 15,896 cubic feet of corn.
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15 ÷ 2 = 7.5
A = πr2h
A ≈ (3.14)(7.5)2(90)
A ≈ (3.14)(56.25)(90)
A ≈ 15,896.25
A ≈ 15,896
The volume of cylindrical water cooler is 1695.6 cubic inches.
The cooler has a radius of 6 inches. Find the height of the
cooler. Use 3.14 for π.
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Write the needed volume formula.
A = πr2h
Substitute known values.
(1695.6) ≈ (3.14)(6)2h
Find the value of the power.
1695.6 ≈ (3.14)(36)h
Multiply.
1695.6 ≈ 113.04h
Divide.
113.04 113.04
15 ≈ h
The height of the water cooler is about 15 inches.
1.
2.
Find the volume of the cylinder. Use 3.14 for .
A circular swimming pool can hold 7850 cubic feet of
water. The diameter of the pool is 50 feet. Find the
height of the swimming pool. Use 3.14 for .
You are helping out in a 2nd grade math class. The
students know you are working on a unit about volume.
One of the 2nd grade students asks you, “What is
volume?” How would explain it to them?