Given the radius or r and the height or h, the volume of a cone can be found by using the formula:
Formula: Vcone = 1/3 × b × h
b is the area of the base of the cone. Since the base is a circle, area of the base = π × r2
Thus, the formula to use to find the volume is Vcone = 1/3 × π × r2 × h
Use π = 3.14
Some examples that will show how to find the volume of a cone.
Example #1:
Calculate the volume if r = 2 cm and h = 3 cm
Vcone = 1/3 × 3.14 × 22 × 3
Vcone = 1/3 × 3.14 × 4 × 3
Vcone = 1/3 × 3.14 × 12
Vcone = 1/3 × 37.68
Vcone = 1/3 × 37.68/1
Vcone = (1 × 37.68)/(3 × 1)
Vcone = 37.68/3
Vcone = 12.56 cm3
Example #2:
Calculate the volume if r = 4 cm and h = 2 cm
Vcone = 1/3 × 3.14 × 42 × 2
Vcone = 1/3 × 3.14 × 16 × 2
Vcone = 1/3 × 3.14 × 32
Vcone = 1/3 × 100.48
Vcone = 1/3 × 100.48/1
Vcone = (1 × 100.48)/(3 × 1)
Vcone = 100.48/3
Vcone = 33.49 cm3
An example showing how to find the volume of an oblique cone.
Since the formula to find the volume of a cone applies to all cones, including oblique cone, we can use the formula V = 1/3(π×r2×h)
Example #3:
Find the volume of an oblique cone with a diameter of 12 ft and a height of 15 ft. Before using the formula, we need to find the radius of the cone.
radius = diameter/2 = 12/2 = 6Voblique cone = 1/3 × 3.14 × 62 × 15
Voblique cone = 1/3 × 3.14 × 36 × 15
Voblique cone = 1/3 × 3.14 × 540
Voblique cone = 1/3 × 1695.6
Voblique cone = 1/3 × 1695.6/1
Voblique cone = (1 × 1695.6)/(3 × 1)
Voblique cone = 1695.6/3
Voblique cone = 565.2 ft3
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