Question Number 59974 by vajpaithegrate@gmail.com last updated on 16/May/19
Answered by tanmay last updated on 16/May/19
$${lateral}\:{surface}\:{area}=\pi{rl} \\ $$$${given}\:{cos}\mathrm{45}^{{o}} =\frac{{h}}{{l}} \\ $$$${l}=\frac{{h}}{{cos}\mathrm{45}^{{o}} }={h}\sqrt{\mathrm{2}} \\ $$$${tan}\mathrm{45}^{{o}} =\frac{{r}}{{h}} \\ $$$${r}={htan}\mathrm{45}^{{o}} ={h} \\ $$$${lateral}\:{zurface}\:{area}=\pi{rl} \\ $$$$=\frac{\mathrm{22}}{\mathrm{7}}×{h}×{h}\sqrt{\mathrm{2}}\: \\ $$$$ \\ $$$$=\pi×\left(\mathrm{20}.\mathrm{025}\right)^{\mathrm{2}} ×\sqrt{\mathrm{2}}\: \\ $$$$\approx\mathrm{401}\sqrt{\mathrm{2}}\:\:\pi \\ $$$${pls}\:{check}... \\ $$
Commented by vajpaithegrate@gmail.com last updated on 16/May/19
$$\mathrm{thank}\:\mathrm{u}\:\mathrm{sir} \\ $$