Answer:
891 ft³
Step-by-step explanation:
<em>First I'll find the volume of the rectangular prism. (l * w * h)</em>
12 * 9 * 7.5
<em>Multiply 12 by 9 to get 108.</em>
108 * 7.5
<em>Now, multiply 108 by 7.5 to get 810. (756 + 54 = 810)</em>
810
<em>Now for the triangular prism. (1/2(l * w * h))</em>
1/2(12 * 9 * 1.5) (I figured the height was 1.5 since the height of the rectangular prism was 7.5; the entire figure's height was 9)
<em>Multiply 12 by 9 to get 108.</em>
1/2(108 * 1.5)
<em>Multiply 108 by 1.5 to get 162. (108 + 54 = 162)</em>
1/2(162)
<em>Multiply 162 by 1/2 to get 81. (162/2)</em>
81
<em>Now add that to 810 to get 891.</em>
810 + 81
891 ft³
The volume of the garage is 891 ft³.