|(pi = = 3.141592...)
Note: "ab" means
"a" multiplied by "b". "a2" means
"a squared", which is the same as "a" times "a".
"b3" means "b cubed", which is the same
as "b" times "b" times
Be careful!! Units count.
Use the same units for all measurements. Examples
cube = a 3
rectangular prism = a b c
irregular prism = b h
cylinder = b h = pi r 2 h
pyramid = (1/3) b h
cone = (1/3) b h = 1/3 pi r 2 h
sphere = (4/3) pi r 3
ellipsoid = (4/3) pi r1 r2 r3
Volume is measured in "cubic" units. The volume
of a figure is the number of cubes required to fill it completely, like
blocks in a box.
Volume of a cube = side times side times side. Since
each side of a square is the same, it can simply be the length of one
If a square has one side of 4 inches, the volume would
be 4 inches times 4 inches times 4 inches, or 64 cubic inches. (Cubic
inches can also be written in3.)
Be sure to use the same units for all measurements.
You cannot multiply feet times inches times yards, it doesn't make
a perfectly cubed measurement.
The volume of a rectangular prism is the length on
the side times the width times the height. If the width is 4 inches, the
length is 1 foot and the height is 3 feet, what is the volume?
NOT CORRECT .... 4 times 1 times 3 = 12
CORRECT.... 4 inches is the same as 1/3 feet.
Volume is 1/3 feet times 1 foot times 3 feet = 1 cubic foot (or 1 cu.
ft., or 1 ft3).