Question

A wooden article was made by scooping out a hemisphere from each end of a solid cylinder. If the height of the cylinder is 10 cm and its base is of radius 3.5 cm, find the total surface area of the article (in $c{m}^2$).

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Answer 1

Height of Cylinder = h =10 cm

Radius of Cylinder = Radius of Hemispheres = r = 3.5 cm

Total Surface area of Article = Curved Surface Area of Cylinder + Inner Surface Area of 1st Hemisphere

+ Inner Surface Area of 2nd Hemisphere

=$2.\pi .r.h+2.\pi .r^2+2.\pi .r^2=2.\pi .r.h+4.\pi .r^2=2.\pi .r(h+2r)$

= ( 2 × $\frac{22}{7}$ × 3.5)(10+(2× 3.5))

=22(17) = 374 $c{m}^2$