Answer: Last option.
Explanation:
The total amount of concrete in the ramp (
) will be the sum of the volume of the rectangular prism (
) and the volume of the triangular prism (
)
![V_t=V_(rp)+V_(tp)](https://img.qammunity.org/2020/formulas/mathematics/high-school/mj2lwsyuuzattesq262clnlsjhb1ap4881.png)
The formulas are:
![V_(rp)=lwh](https://img.qammunity.org/2020/formulas/mathematics/high-school/w8wu9o8m05lqec2pz6e54u0kh6u0moz48w.png)
Where "l" is the lenght, "w" is the width and "h" is the height.
![V_(tp)=(bhl)/(2)](https://img.qammunity.org/2020/formulas/mathematics/high-school/dog75cppopmwshlujim2wa87yjfpaa9yku.png)
Where "l" is the lenght, "b" is the base and "h" is the height.
Substituting, we get:
![V_t=V_(rp)+V_(tp)\\\\V_t=lwh+(bhl)/(2)\\\\V_t=(18in)(6in)(6in)+((8in)(6in)(18in))/(2)\\\\V_t=1,080in^3](https://img.qammunity.org/2020/formulas/mathematics/high-school/6d1gyffnkmzeisynagx5swev27pibdj1ny.png)