
so, let's first change the bounds from 1 to 9, so we'll be dropping the indices by 1, in order to do the variable "n".
however, let's use a variable hmmm say "k", where "k" is the value of "n" beginning at 1, thus
k = n - 1.
however, if k = n - 1, then
k + 1 = n. So let's use those fellows then,
1: 48
2: 18
3: 73
Hope this helps you!
This is more like math homework
A triangular prism Vol. = area (A) of the triangular base × height (h) of prism
A triangular pyramid V = A × 1/3 h
So since they have same base A and h, the V of the pyramid will be exactly 1/3 the V of the prism
You can use any letter but when you label it x you find x