find the missing width in the diagram.

Explanation:

Step1: Analyze the horizontal lengths

The total horizontal length is 15 m. There are two 5 - m lengths and a 3 - m length accounted for.

Step2: Set up the equation

Let the missing width be $x$. Then $x + 5+5 + 3=15$.

Step3: Solve the equation

$x=15-(5 + 5+3)$. $x = 15 - 13$. $x = 2$.

Answer:

2