4400 Higher November 2004 Paper 3 Q18
18 A cone has base radius \(r\) cm and vertical height \(h\) cm.
The volume of the cone is \(12\pi\) cm3.
Find an expression for \(r\) in terms of \(h\).
(3)
| Scheme | Marks |
|---|---|
| \(\frac{1}{3}\ r^2h = 12\) | M1 |
| \(r^2 = \dfrac{36}{h}\) | M1 |
| \(r = \dfrac{6}{\sqrt{h}}\) oe | A1 |
| (3) | |
| (3 marks) |
Notes
M1: \(\frac{1}{3}\ r^2h = 12\) M0
M1: \(r^2 = \dfrac{36}{h}\) M1