Question

the length of the rectangle is equal to three times its width. if the perrimeter is equal to 72 feet what is the length of the rectangle?

Answer 1

length = 3a
width = a
Perimeter = 2(length + width)
therefore
72 = 2(3a + a)
and now solve for a! You will get both sides

Answer 2

\[2length+2width=72\]
\[length=3x, and, width =x\]
Solve for x, find the length
Done!