Question

To develop critical and analyzing skills

amongst her children, maths teacher showed her students a video of 3D objects and asked the students to

identify the 3D objects. One such video was of PWD workers constructing road using road roller. The

cylindrical road roller made of iron was 1m long. Its inner diameter was 54cm and thickness of the iron

sheet rolled into the road roller is 9cm.

1) What is the outer radius of the road roller ?

a) 22cm

b) 44cm

c) 36cm

d) 11cm

2) What is the outer curved surface area of the road roller ?

a) 1548π cm2

b) 220π cm2

c) 7200π cm2

d) 440π cm2

3) If PWD workers constructed 1584 m2

road in one day, find the number of revolutions that the

road roller made.

a) 500

b) 1000

c) 700

d) 100

4) What will be the amount of iron used in road roller ? ( take π = 3.14 )

a) 178038 cm3

b) 406944 cm3

c) 228906 cm3

d) 356076 cm3



5) If 1cc of iron weighs 10grams, what will be the weight of the road roller ? ( answer in kg )

a) 1780.38 kg

b) 4069.44 kg

c) 2089.06 kg

d) 3560.76 kg​

Answer 1

Answer:

The inner curved surface area = 2πr × Height, the outer curved surface area = 2πR × Height.