### Home > ACC7 > Chapter cc28 > Lesson cc28.1.1 > Problem 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? Homework Help ✎

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: 3*x* − 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.