A wooden article was made by scooping out a hemisphere from each end of a solid cylinder
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
Original height of cylinder = 10 cm
Base radius of cylinder = 3.5 cm
So, base radius of hemisphere = 3.5 cm (same as that of cylinder)
Total surface area of article = Curved surface area of cylinder + Curved surface areas of 2 hemispheres
CSA of cylinder = 2πrh
= 2 × 22/7 × 3.5 × 10
= 220 cm2
Surface areas of two hemispherical scoops = 2 × 2πr²
= 4 × 22/7 × 3.5 × 3.5
= 154 cm2
Total surface area of article = 220 + 154
= 374 cm2