Question

The radius of the base of a cylindrical wooden block is 5cm and its volume is 1100cu.cm. How many disc of radius 5cm and 2cm can be cut from this block of wood ??

Answer 1

$v = \pi {r}^{2} h \\ 1100 = \frac{22 \times 5 \times 5 \times h}{7} \\ h = \frac{1100 \times 7}{22 \times 25} = \frac{100 \times 7}{25} = 28cm \\ no. \: of \: disc = \frac{28}{2} = 14$