Question

Please show me the step on how to do this. I know the answer but how do you get it.

A rectangular garden with a 4-feet wide cement sidewalk is shown. The cement for the sidewalk is 1 foot deep.

What volume of cement is needed for the sidewalk?

A) 96 cubic feet
B) 120 cubic feet
C) 192 cubic feet
D) 240 cubic feet

Answer 1

So, to find the volume of just the cement part, you need to find the volume of the whole shape, then find the volume of the garden. then subtract them to find the volume of just the cement sidewalk.

volume of garden: 16 x 6 x 1 (l x w x h)= 96 ft3

volume of whole: length=16+4+4=24, width=6+4+4=14, height=1
you have to add 4 to each sides of the length and width to get the entire length.
volume of whole=24 x 14 x 1=336 ft3

now subt.

336-90=246 ft3 would be the volume of the cement walkway.