## Math Review – Formulas Chapter Practice Set 3, Prob. 8.) “Using fractions to rewrite measurements”.

Practice set three, number eight. How many
cubic feet of cement will it take to make a rectangular-shaped driveway that is forty-five
feet long, twelve feet wide, and six inches in depth? Use the formula: “V”=”L” “W” “H”.
In this formula, “V” represents the volume of cement, “L” the length of the driveway,
“W” the width, and “H” the height or sometimes called the depth. No symbol in between these
letters implies multiplication. So let’s try this problem. When I use my formula, I need
to put in all units of feet because the problem asks for my answer to be in cubic feet. So
I have the width and length already in feet but the hieght, or depth, is in inches. I’m
going to rewrite that in units of feet. Six inches is six inches out of the twelve inches
in one whole foot. So six inches is the same thing as six twelfths of a foot. Okay, going
to my formula, the volume equals length, forty-five, times width, twelve, times the depth, six
twelfths. And all of theses again are in feet. I’m going to have a scietific calculaotr
help me evaluate this formula now that my numbers are in. And I have forty-five times twelve,
times six twelfths. I’ll enter that using a fracton key, six fraction key twelve and
when I press equals my answer appears. Two hundred-seventy, I have feet feet feet, so
my volume answer will be in cubic feet. Part b, asks us: since the cement is sold by the
cubic yard, convert your answer using this conversion factor: one cubic yard is twenty-seven
cubic feet. What I will do for that is have twenty-seven cubic feet makes one cubic yard,
so two hudred-seventy divided by the twenty seven will give me my cubic yard answer. And
that is ten cubic yards.