Question

The stairway shown is made out of solid concrete. The height of each step is four inches and the width is 10 inches. The length is 6 inches. What is the volume, in cubic inches, of the concrete used to create this stairway?

Answer 1

Option B

Explanation:

We have to calculate the volume of concrete used to create the stairway given in the picture.

Volume of the stairway = volume of small stairway + volume of larger stairway

Dimensions of Large stairway = 10 in × 6 in × (4+4)in

= 10 in × 6 in × 8 in.

Therefore, volume of large stairway = 480 in³

Dimensions of small stairway = 10 in × 6 in × 4 in

= 240 in³

Total volume = 480 + 240

= 720 in³

Option B is the answer.

Answer 2

The volume of the stairway is

720 cubic inches

Explanation:

we know that

The volume of the stairway is equal to the volume of two rectangular prism

The volume of the rectangular prism is equal to

`V=LWH`

Find the volume of the larger rectangular prism

we have

`L=6\ in`

`W=10\ in`

`H=4+4=8\ in`

substitute

`V=(6)(10)(8)=480\ in^(3)`

Find the volume of the smaller rectangular prism

we have

`L=6\ in`

`W=10\ in`

`H=4\ in`

substitute

`V=(6)(10)(4)=240\ in^(3)`

Find the volume of the stairway

Adds the two volumes

`V=480+240=720\ in^(3)`