Question

Find
i) The total surface area of a closed cylindrical petrol storage tank whose diameter 4.2m and height 4.5m.
ii) How much steel sheet was actually used, if 1/12 of the steel was wasted in making the tank.

Answer 1

(1)total surface area of closed petrol tank =2πr^2+2πrh
=2πr(r+h)
=2 x 22/7 x (2.1) {2.1+4.5}
=2 x 22 x (0.3)(6.6) m^2
=87.12 m^2

(2) actual steel used =total area +total area/12 =87.12 +(87.12)/12
=87.12 +7.26=94.38 m^2

Answer 2

$\underline{\textsf{Given:}}$

$\textsf{Diameter of cylindrical petrol storage tank is 4.2 m and its height is 4.5 m}$

$\underline{\textsf{To find:}}$

$\textsf{(i)Total surface closed cylindrical storage tank}$

$\textsf{(ii)Amount of steel used}$

$\underline{\textsf{Solution:}}$

$\underrline{\mathsf{Formula\;used:}}$

$\boxed{\mathsf{Total\;surface\;area\;of\;cylinder=2\,\pi\,r(h+r)\;square\;units}}$

$\mathsf{Radius\;cylindrical\;storage\;tank=\dfrac{Radius}{2}=\dfrac{4.2}{2}=2.1\,m}$

$\underrline{\textsf{Total suface area cylindrical storage tank}}$

$\mathsf{=2\,\pi\,r(h+r)}$

$\mathsf{=2{\times}\dfrac{22}{7}{\times}2.1(4.5+2.1)}$

$\mathsf{=2{\times}22{\times}0.3(6.6)}$

$\mathsf{=13.2(6.6)}$

$\mathsf{=\bf\,87.12\;square\;m}$

$\underline{\mathsf{Amount\;of\;metal\;actually\;used}}$

$\mathsf{=Amount\;of\;metal\;used\;for\;cylinderr+Amount\;of\;metal\;wasted\;to\;make\;it}$

$\mathsf{=87.12+\dfrac{1}{12}{\times}87.12}$

$\mathsf{=87.12+7.26}$

$\mathsf{=\bf\,94.38\;square\;m}$

$\underrline{\textsf{Find more:}}$

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