Answer:
<h2>t = 9in</h2>
Step-by-step explanation:
The formula of a volume of a prism:

<em>B</em><em> - area of a base</em>
<em>H</em><em> - height</em>
In the base is the triangle.
The formula of an area of a triangle:

<em>b</em><em> - base</em>
<em>h</em><em> - height</em>
We have <em>V = 247.5 in³, b = 5 in, H = 11 in</em> and <em>h = t</em>.
Therefore:

Put them to the formula of a volume:


<em>divide both sides by 27.5</em>
