Question

What is the approximate volume of a cylinder with a height of 2 ft and a radius of 6 ft?

Use 3.14 to approximate pi.
Express your answer in hundredths.

Answer 1

The are of a cylinder is equal to the area of its base, times its height.

The base is a circle.

Answer 2

The area of a circle is π r^2, where r is the radius.

Answer 3

Im So Confused @UnkleRhaukus

Answer 4

Can you compute the area of the circle?

A = π r^2
= 3.14 x ( 6 ft )^2
=

Answer 5

10.5

Answer 6

did you square the 6?

Answer 7

idk how

Answer 8

6^2 = 6 x 6

Answer 9

ooo yea

Answer 10

so you have

A = π r^2
= 3.14 x ( 6 ft )^2
= 3.14 x 6 x 6 ft^2
=

Answer 11

113.04

Answer 12

great!,
so the area of the circular base is 113.04 ft^2

Answer 13

Now we can find the volume of the cylinder, but multiplying by the height

Answer 14

Thanks

Answer 15

ok

Answer 16

What do you get?

Answer 17

idk

Answer 18

ooo

Answer 19

V = 113.04 ft^2 x 2 ft
= 113.04 x 2 ft^3
= . . .

Answer 20

226.08

Answer 21

That's it.

Answer 22

THANKS!!

Answer 23

1 More

Answer 24

the units are ft^3.

Answer 25

Yes

Answer 26

ok, next one

Answer 27

The radius of a cylinder is 15 cm. The volume of the cylinder, found using 3.14 to approximate pi, is 19,782 cm3.

What is the height of the cylinder?

Express your answer as a whole number.

Answer 28

As before, for a cylinder the volume is V = Ah = 2 π r^2 h

Solve V = 2π r^2 h for h.

Answer 29

???

Answer 30

find an equivalent equation that is like

h = ........

Answer 31

V = 2π r^2 h

divide both sides of the equation by 2 π r^2

Answer 32

???????????

Answer 33

V / 2π r^2 = 2π r^2 h / 2π r^2

Answer 34

simplify the righthand side

Answer 35

19782

Answer 36

cancel the terms common to both the numerator and denominator

Answer 37

706

Answer 38

V / 2π r^2 = h

or switching it around

h = V / ( 2π r^2 )

now plug in the values