Answer:
a,c
Step-by-step explanation:
we know that
the volume of a solid oblique pyramid is equal to

where
B is the area of the base
h is the height of the pyramid
in this problem we have that
B is a square

where
<u>
</u>
so


substitute in the formula of volume
![V=\frac{1}{3}*x^{2}*(x+2)\\ \\V=\frac{1}{3}*[x^{3} +2x^{2}]\ cm^{3}](https://tex.z-dn.net/?f=V%3D%5Cfrac%7B1%7D%7B3%7D%2Ax%5E%7B2%7D%2A%28x%2B2%29%5C%5C%20%5C%5CV%3D%5Cfrac%7B1%7D%7B3%7D%2A%5Bx%5E%7B3%7D%20%2B2x%5E%7B2%7D%5D%5C%20cm%5E%7B3%7D)
therefore
<u>the answer is</u>
![V=\frac{1}{3}*[x^{3} +2x^{2}]\ cm^{3}](https://tex.z-dn.net/?f=V%3D%5Cfrac%7B1%7D%7B3%7D%2A%5Bx%5E%7B3%7D%20%2B2x%5E%7B2%7D%5D%5C%20cm%5E%7B3%7D)
75 * 1000/3600 = 20.8333333
You just need to multiply with 1000 to get m from km and divide by 3600 because you are converting hours in seconds.