Answer:
A
Step-by-step explanation:
We know the following:

so the segment EF is equal to

and here we can do a trick :)

you see it's the same

now we plug the values given

so it's option A
For the volume of triangular prism, volume = 0.5xaxbxc
=0.5x10x7x6
=210cm^3
Answer:
if you want the base and the height you have to give me number or do you want the formula ?