The staircase has three parallelogram-shaped panels that are the same size. The horizontal distance between each panel is 4.25 inches. What is the area of one panel? Explain your thinking

First, you need to find the width of the parallelogram as you already know the length which is 20.5 in

Given that the total is 50.5 in wide and the gap in between each measures 4.25 in.

There are two gaps so 2 × 4.25 = 8.5 in

Subtract this amount from the total width of 50.5 in so that you're only left with the actual measures for the width of the three parallelogram

50.5 - 8.5 = 42 inches

The total width of the three parallelogram excluding the two gaps is 42 inches.

Divide this in three so that you're left with the width for only one parallelogram.

42 ÷ 3 = 14 inches

Now you know that the length is 20.5in and the width is 14in.

The area formula of a parallelogram is A = l × w

A = 20.5 × 14
A = 287 square inches