Volume is the measure of cubic units it takes to fill a space right?

Question

my problem is the radius is 10inches, and the height is 4 feet, so why does the height (4 feet) have to convert to 48 inches inorder to finish the problem correctley... I have all ready got the problem right just don't quiet understand it?

Answer 1

When calculating a volume, all units must be the same.
This is a fact so accept it and proceed accordingly.
Your example may be done using inches or feet but not a mixture of both.
Assuming that you are considering a cylinder:-
V1 = π r² h
V1 = π x 10² x 48 in³
V1 = 4800 π in ³
or
V2 = π x (10/12)² x 4 ft ³
V2 = 400 π / 144 ft²

Now 1 ft³ = 12 x 12 x 12 in³
1 ft³ = 1728 in³
V2 = (400 π / 144 ) x 1728 in³
V2 = 4800 π in³ = V1
ie the same volume.

Answer 2

If I asked you to calculate the volume of a cube whose dimensions were 1ft x 12 in x 1/3yd., would you tell me it's 4 cubic units?.Of course not! It's a cubic foot in volume, pure and simple.
A failure to use compatible units is one big reason for getting the wrong answer to problems. In your problem, you can use ft., or you can use inches. Not a combination. NEVER.

Answer 3

When you are calculating volume you have to use the same unit of measure.

Answer 4

i think your solving is a cylinder
A = π r² h
A = π (10 inch)² (48 inch)
A = 15079.64 inch inch inch
A = 15079.64 inch³