Answer
$5728\;ft^3$.
Work Step by Step
Divide the figure into three sections.
First rectangular section:-
Height $=20\;ft$
Length $=8\;ft$
Width $=8\;ft$
Volume $=$ Height $\times$ Length $\times$ Width
$\Rightarrow V_1=(20\;ft)\times(8\;ft)\times(8\;ft) $
$\Rightarrow V_1=1280\;ft^3 $
Second rectangular section:-
Height $=20-12=8\;ft$
Length $=60-20-8=32\;ft$
Width $=8\;ft$
Volume $=$ Height $\times$ Length $\times$ Width
$\Rightarrow V_2=(8\;ft)\times(32\;ft)\times(8\;ft) $
$\Rightarrow V_2=2048\;ft^3 $
Third rectangular section:-
Height $=15\;ft$
Length $=20\;ft$
Width $=8\;ft$
Volume $=$ Height $\times$ Length $\times$ Width
$\Rightarrow V_3=(15\;ft)\times(20\;ft)\times(8\;ft) $
$\Rightarrow V_3=2400\;ft^3 $
Total volume
$\Rightarrow V=V_1+V_2+V_3$
$\Rightarrow V=1280\;ft^3+2048\;ft^3+2400\;ft^3$
$\Rightarrow V=5728\;ft^3$.
