Question

a road roller 140 cm long and 77 cm in diameter makes 300 revolutions to level a field completely. find area of the field.

Answer 1

d=77cm
c= πd
=22/7×77
=22×11
=242cm
now,
area of field =140×242×300(coz revolu....=300)
=10,164,000 sq cm
=1016.4 sq m
( 1 sq m = 10000 sq cm )

Answer 2

Answer:

10154760 sq.cm.

Step-by-step explanation:

Height of road roller = 140 cm

Diameter of road roller = 77cm

Radius of road roller = $\frac{Diameter}{2} =\frac{77}{2}$38.5 cm

Road roller is in the shape of cylinder

Curved surface area of cylinder = $2 \pi r h$

Curved surface area of road roller = $2 \times 3.14 \times 38.5 \times 140$

                                                        = $33849.2cm^2$

Area covered in 1 revolution = 33849.2 sq.cm

Area covered in 300 revolutions = $33849.2 \times 300=10154760$

Since a road roller makes 300 revolutions to level a field completely.

Hence the area of the field is 10154760 sq.cm.