Question

what is the missing length? area of shaded region = 86.4 cm² u = centimeters

Explanation:

Step1: Recall triangle area formula

The area formula for a triangle is $A=\frac{1}{2}\times base\times height$. Here, the base is 18 cm and the height is $u$, and the area $A = 86.4$ $cm^{2}$.

Step2: Solve for $u$

We have the equation $86.4=\frac{1}{2}\times18\times u$. First, simplify the right - hand side: $\frac{1}{2}\times18 = 9$. So the equation becomes $86.4 = 9u$. Then, divide both sides by 9: $u=\frac{86.4}{9}$.

Answer:

9.6