Answer:
891 ft³
Explanation:
First I'll find the volume of the rectangular prism. (l * w * h)
12 * 9 * 7.5
Multiply 12 by 9 to get 108.
108 * 7.5
Now, multiply 108 by 7.5 to get 810. (756 + 54 = 810)
810
Now for the triangular prism. (1/2(l * w * h))
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)
Multiply 12 by 9 to get 108.
1/2(108 * 1.5)
Multiply 108 by 1.5 to get 162. (108 + 54 = 162)
1/2(162)
Multiply 162 by 1/2 to get 81. (162/2)
81
Now add that to 810 to get 891.
810 + 81
891 ft³
The volume of the garage is 891 ft³.