Question

A triangular sail has two sides the same length. The third side is 9 ft shorter than either of the equal sides. The perimeter of the sail is 63 ft. How long is the shortest side?

If you could show or explain your work, that would be great.

Answer 1

You already know that one side is 9ft shorter than the rest, so subtract 9 from 63: 63-9=54
Now, with the extra 9 feet gone, you know that the three sides are equal. So, divide 54 by 3:
54/3=18 feet
The shortest sides are 18 feet and the longest side is 27 feet.
You can check by adding the lengths of the three sides together:
18+18+27
=36+27
=63

If you need to write it out as an equation, it would be 3x+9=63, where x is equal to the length of the side of the sail.