Question

Find the radius of a cylinder with a volume of 108ft and height of 12 ft

Answer 1

1.69 ft

Explanation:

V = πr²h formula of a cylinder.

Volume = 108 ft

Height = 12 ft

Radius = r

V = πr²h

108 ft = 22/7 × r² × 12 ft

π = 22/7 or 3.14

108 ft = 264/7r²

108 ft = 37.71r²

divide both sides by 37.71

108 ft/37.71 =r²

2.86 ft = r²

square root both side

√2.86 ft = √r²

the square cancels the square root

1.69 ft.

To check

V = πr²h

108 = 22/7 × (1.69)² 12

108 = 22/7 × 2.8561 × 12

108 = 107.61≈108

108 ft = 108 ft.

Answer 2

1.69 ft (approx.)

Explanation:

Formula for Volume of cylinder: pi x radius squared x height

Plug in 108 for volume, 3.14 for pi and 12 for height:

108 = 3.14 x r squared x 12

Multiply 3.14 and 12

108 = 37.68 x r squared

Divide both sides by 37.68

2.87 = r squared

"Unsquare" both sides (square root)

1.69 ft. = radius (approximate answer, rounded to nearest hundredth)