A solid right cylinder is of height pi cm If its lateral surface area is half its total surface area...........

Quantitative Aptitude (CDS) Mensuration 3D

A solid right cylinder is of height π cm. If its lateral surface area is half its total surface area, then the radius of its base if

π/2 cm

π cm

1/π cm

2/π cm

Let radius of cylinder be r

$\small LSA\: =\: 2\pi rh =2\pi r(\pi )$

$\small TSA\: =\: 2\pi r(h + r) = 2\pi r(\pi +r)$

According to question

TSA = 2 LSA

$\small 2\pi r(\pi + r) = 2(2\pi r(\pi ))$

$\small \pi + r = 2\pi , r = 2\pi$

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