The two rectangles above are similar. If a = 4 in, b = 8 in, and d = 16 in, what is the length of c?

Since the two rectangles are similar, their corresponding sides are proportional.

Let x be the length of side c.
Using the property of similar rectangles, we have:

a / b = c / d

Substitute the given values:

4 / 8 = x / 16

Simplify the equation:

1/2 = x / 16

To solve for x, multiply both sides by 16:

x = 1/2 * 16
x = 8 in

Therefore, the length of side c is 8 inches.