This question is way over my head, its the last question in my txt book for this chapter and the only one I dont fully understand and get.
Q. 10. A sector of a circle with radius 5cm and an angle of PI/3(as in u know the mathematical pi) subtended at the centre is cut out of cardboard. It is then curved around to form a cone. Find its exact surface area and volume.
answer for surface area is
25 PI / 6
(ive figured surface area out already)
ok i know the exact value of the surface area, but how do i get the volume?
the answer in the back for volume is
V = 125 35 PI
648 cm cubed
the decimal form of this answer is = 3.585245522
(not 35 is only under the square root just to clarify)
so just figuring out the volume of this stupid cut out sector is my problem now : (
thx all help appreciated