Pyramid volume

What did people get for the pyramid volume and how?

I got 98.8cm^2
I have no idea if I'm right but I can talk you through how I got it.
I first worked out the radius for the base of the smaller cone. I did this by working out the scale factor between the lengths, which is 1.6 recurring. I then divided 3 by the scale factor to get the radius for the base of the smaller cone as 1.8cm.
I then used the formula given to worked out the curved surface area of the large cone, which I got as 30pi, and the curved surface are of the smaller cone, which I got as 54/5 pi. (you can check this because dividing 30pi by the scale factor twice gives you 54/5 pi)
I then took away the curved surface area of the small cone away from the curved surface area of the large cone to get the curved surface area of the frustrum as 96/5 pi.
You then need to work out the area of the top and bottom spheres of the frustrum using pir^2, which gives you 81/25pi and 9pi, respectively.
Add the curved surface are of the frustrum to the area of the top and bottom spheres to give you a total surface area of 786/25pi, or 98.8 to 3 significant figures