Question

A cylindrical roller is used to paint a wall. The length of roller is 1.4 m and its diameter is 0.7 m.
If the roller rolls 50 times to cover the wall completely, find the area of the wall.

Answer 1

Answer:

Area covered = Curved surface × Number of revolutions

r=

2

1.4

=0.7 m

h=2 m

Curved surface = 2πrh=2×

7

22

×0.7×2=8.8 m

2

Hence,

Area covered = 8.8×5=44 m

2