Question

type the correct answer in the box. use numerals instead of words. if necessary, use / for the fraction bar.
the chang family puts up holiday lights around their isosceles trapezoidal window. they use 20 feet of lights to go around the frame.
how long is each leg of the window?
each unknown leg is
ft long.

Explanation:

Step1: Set up perimeter equation

The perimeter of the isosceles trapezoid is the sum of all sides, equal to 20 ft.
$$x + x + x + \frac{x}{3} = 20$$

Step2: Combine like terms

Convert all terms to thirds to add them.
$$\frac{3x}{3} + \frac{3x}{3} + \frac{3x}{3} + \frac{x}{3} = 20$$
$$\frac{3x+3x+3x+x}{3} = 20$$
$$\frac{10x}{3} = 20$$

Step3: Solve for x

Multiply both sides by 3, then divide by 10.
$$10x = 20 \times 3$$
$$10x = 60$$
$$x = \frac{60}{10}$$

Answer:

6