Procedure Step 1 Let the circumference of base =22 cm and height of cylinder =10 cm. Step2 Cut a rectangle of length equal to the circumference of base (22 cm ) and breadth equal height of cylinder(10 cm). Step3 Gently curve the paper so that the two shorter sides come closer , put a cello tape. Step4 To make the top and base of cylinder ,firstly calculate the radius of the base and the top circles. 2 X Pi X r = 22 2 X 22/7 X r = 22 , r=7/2
Step5 Cut 2 circles of radii 3.5 cm each. Step 6 Cover the base and the top of the cylinder with the circles using a cello tape. Step7 Calculate the curved surface area by removing top and base circles. Curved surface area of cylinder =area of rectangle =lenght *breadth = 2 Pi r * h = 2 Pi r h = 22*10 = 220 cm sq. Total surface area = area of rectangle + 2[area of circle] =2 pi r h +2[pi r*r] =220 + 2[22/7 * 7/2 * 7/2] =220 + 77 =297 cm sq Observations The rectangle transforms into a cylinder. The height of the cylinder is breadth of the rectangle. The circumference of the base of the cylinder is the length of the rectangle.