### Home > CC2 > Chapter 8 > Lesson 8.1.1 > Problem8-11

8-11.

Write an equation to represent this problem and find the unknown side lengths. Use the 5-D Process to help you organize your thinking and to define your variables, if you need to do so. Remember to define your variable.

A trapezoid has a perimeter of $117$ cm. The two shortest sides have the same length. The third side is $12$ cm longer than one short side. The final side is $9$ cm less than three times one short side. How long is each side of the trapezoid?

Perimeter is the sum of the lengths of all the sides.

Create an expression comparing each side with the shortest side, represented by $x$.

Two Shortest Sides: $x$
Third Side: $12+x$
Fourth Side: $3x-9$
Perimeter: $117$ cm

Shortest Sides: $19$ cm
What are the other side lengths?
Be sure to know how to get this length and the other lengths.