A wooden article was made by scooting out a hemisphere from each end of a cylinder, as shown in the figure. If the height of the cylinder is 20 cm and its base is of diameter 7 cm, find the total surface area of the article when it is ready.

The wooden article was made by scooting out a hemisphere from each end of a cylinder

Let the radius of cylinder be r cm and height be h cm.

Height of cylinder = h = 20 cm

Base diameter of cylinder = 7 cm

Base radius of cylinder = r = diameter ÷ 2 = 7/2 cm = 3.5 cm

Lateral Surface area of cylinder = 2πrh

= 2 × 22/7 × 3.5 × 20 cm2

= 2 × 22/7 × 3.5 × 20 cm2

= 440 cm2

Since, the wooden article was made by scooting out a hemisphere from each end of a cylinder

Two hemispheres are taken out in total

Radius of hemisphere = 3.5 cm

Lateral Surface area of hemisphere = 2πr2

= 2 × 22/7 × 3.5 × 3.5 cm2

= 77 cm2

Total Surface area of two hemispheres = 2 × 77 cm2 = 154 cm2

Total surface area of the article when it is ready = Lateral Surface area of cylinder + Lateral Surface area of hemisphere

Total surface area of the article when it is ready = 440 cm2 + 154 cm2

= 594 cm2

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
Surface Area and Volume49 mins
Surface Area and Volumes43 mins
RD Sharma | Imp Concepts : Surface Area And Volumes43 mins
RD Sharma | Imp. Qs. From Surface Area And Volumes47 mins
IMP Formula's and Qs For Surface Area and Volumes45 mins
Quiz | Surface Area and Volumes42 mins
RD Sharma | Area of Sector and Segment61 mins
RD Sharma | Area of Sector and Segments25 mins
Throwing the Light on Area of Sector43 mins
Foundation | Let's Understand Some High Level Concepts41 mins
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
view all courses