# A cylindrical roller 2.5 m in length, 1.75 m in radius when rolled on a road was found to cover the area of 5500 m². How many revolutions did it make?

**Solution:**

Given, a cylindrical roller is 2.5 m in length

The radius of cylindrical roller is 1.75 m

The roller when rolled on a road was found to cover an area of 5500m²

We have to find the number of revolutions made by the roller.

Area covered in one revolution = curved surface area of the cylinder

Curved surface area of cylinder = 2πrh

Where, r is the radius of the cylinder

h is the height of the cylinder

Given, r = 1.75 m

h = 2.5 m

Area covered in one revolution = 2(22/7)(1.75)(2.5)

= 192.5/7

= 27.5 m²

Number of revolutions made by the cylinder = total area covered by the cylindrical roller / area covered in one revolution

= 5500/27.5

= 200

Therefore, the number of revolutions made is 200

**✦ Try This: **A cylindrical roller 3 m in length, 1.25 m in radius when rolled on a road was found to cover the area of 4500 m². How many revolutions did it make?

**☛ Also Check: **NCERT Solutions for Class 9 Maths Chapter 13

**NCERT Exemplar Class 9 Maths Exercise 13.3 Problem 7**

## A cylindrical roller 2.5 m in length, 1.75 m in radius when rolled on a road was found to cover the area of 5500 m². How many revolutions did it make?

**Summary:**

A cylindrical roller 2.5 m in length, 1.75 m in radius when rolled on a road was found to cover the area of 5500 m². 200 revolutions were made by the roller

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