Question

if these two shapes are similar, what is the measure of the missing length b?
(image of two rectangles: smaller one with height 3 ft and width 1 ft; larger one with width 3 ft and height b)
b = \boxed{} feet

Explanation:

Step1: Set up similarity proportion

$\frac{1}{3} = \frac{3}{b}$

Step2: Cross-multiply to solve for b

$1 \times b = 3 \times 3$

Step3: Calculate the value of b

$b = 9$

Answer:

9 feet