Question

8. Awooden article was made by scooping out a hemiphere from each end of
a solid cylinder, as shown in the figure. If the height of the cylinder is 10 cm.
and its radius of the base is of 3.5 cm, find the total surface area of the
article.​

Answer 1

Answer:

let the original height of cylinder = 10cm

base radius of cylinder = 3.5cm

so base radius of hemisphere = 3.5cm(same as that of cylinder)

The total surface area would be the sum of curved surface area of cylinder and the surface areas of 2 hemispheres.

surface area of cylinder = 2πrh

surface area of one hemisphere = 2πr²

$$\begin{lgathered}TSA=2 \pi rh+2(2 \pi r^2)\\TSA=2 \pi rh+4 \pi r^2\\TSA=2 \pi r(h+2r)\\TSA=2* \frac{22}{7}*3.5(10+2*3.5)=22*(10+7)\\TSA=\boxed{374\ cm^2}\end{lgathered}$$