A well is $7.2 m$ deep. The cost of cementing its inner surface at $75$ paise per $d m^{2}$ is Rs. $11880$ . Determine the radius of the wall.

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Solution

Surface area of cylinder $= 2 π r h$

$2 \times 3.14 \times r (7.2) = 45.216 r m^{2}$

$45.216 r \times 0.75 = 11880$

$r = \frac{11880}{33.912} = 350.31 m$

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A well is 7.2m deep. The cost of cementing its inner surface at 75 paise per dm2 is Rs. 11880. Determine the radius of the wall.

Surface area of cylinder =2πrh2×3.14×r(7.2)=45.216rm245.216r×0.75=11880r=1188033.912=350.31m

A well is $7.2 m$ deep. The cost of cementing its inner surface at $75$ paise per $d m^{2}$ is Rs. $11880$ . Determine the radius of the wall.

Surface area of cylinder $= 2 π r h$

$2 \times 3.14 \times r (7.2) = 45.216 r m^{2}$

$45.216 r \times 0.75 = 11880$

$r = \frac{11880}{33.912} = 350.31 m$