ABC26GN5037 · Volume and Surface Area

Volume of sphere $=\left(\frac{4}{3} \pi \times 15 \times 15 \times 15\right) \mathrm{cm}^{3}$. $$\text { Volume of cone }=\left(\frac{1}{3} \pi \times 15 \times 15 \times 15\right) \mathrm{cm}^{3} .$$ Volume of wood wasted = $$\begin{aligned} & {\left[\left(\frac{4}{3} \pi \times 15 \times 15 \times 15\right)-\left(\frac{1}{3} \pi \times 15 \times 15 \times 15\right)\right] \mathrm{cm}^{3} .} \\ & \quad=(\pi \times 15 \times 15 \times 15) \mathrm{cm}^{3} . \\ & \therefore \text { Required percentage }=\left(\frac{\pi \times 15 \times 15 \times 15}{\frac{4}{3} \pi \times 15 \times 15 \times 15} \times 100\right) \%=75 \% . \end{aligned}$$