Question

Question 9
A wooden article was made by scooping out a hemisphere from each end of a solid cylinder, as shown in figure. 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.

Answer 1

Radius = 3.5 cm, height = 10 cm
Total surface area of structure = Curved surface area of cylinder + Curved surface area of two hemispheres
Curved surface area of cylinder
$=2\pi rh$
$=2\pi \times 3.5\times 10$
$=70\pi c{m}^2$
Surface area of a hemisphere
$=2\pi r^2$
$=2\pi \times {3.5}^2$
$=24.5\pi$
Total surface area = $70\pi +2\times \left(24.5\pi \right)$
$=70\pi +49\pi$
$=119\pi$
$=119\times \frac{22}{7}=374c{m}^2$