2 questions

[VVVCCCEEE]

Much help needed, thanks

[M909]

For the cone question I would calculate the volume of the original cone, then the volume of the end that has been cut off, then subtract that from the original to get the remaining volume.

For the prism (I'm assuming you want volume?), calculate the trapezoid area with Area = 0.5*(top length + bottom length)*height, then multiply this by the width

[VVVCCCEEE]

Could you give me the equation for the cone question. I did 1/3pi(5)^2x30-1/3pi(2.5)^2 x25 but the ans says 782

[S200]

Could you give me the equation for the cone question. I did 1/3pi(5)^2x30-1/3pi(2.5)^2 x25 but the ans says 782

The book's correct.
Full volume of the cone is 785.4, by using the formula, with h(30) and r(5)


Now, where you probably went wrong. The upper part of the cone uses h(5), and the radius has to be ratio'ed back to meet this - You can use similar triangles or Pythagoras, doesn't really matter

So, with that h and r, we get V ≈ 3.64.
Minus this from the first value and you get 781.76, ∴ 782