If the length of the rectangle is x cm, then the width becomes 10 minus x cm because the total perimeter is 20 cm. Therefore, the area of the rectangle is x multiplied by 10 minus x.
A wire of length 20 cm is bent in different ways to form rectangles. For example, we can have a rectangle with length 7 cm and width 3 cm. We can also have one of length 5.5 cm and width 4.5 cm. (Think of a few more ways of forming such rectangles.) Can you write an expression for the area of such rectangles?
Share
The total length of the wire is 20 cm, so the perimeter of the rectangle is 20 cm. Since the perimeter formula is 2 multiplied by length plus width, the sum of length and width becomes 10 cm. If the length is x cm, then the width will be 10 minus x cm. The area of a rectangle is length multiplied by width. Therefore, the expression for the area of the rectangle is x multiplied by 10 minus x or 10x minus x square.
For more NCERT Solutions for Class 9 Maths Ganita Manjari Chapter 2 Introduction to Linear Polynomials (2026-27):
https://www.tiwariacademy.com/ncert-solutions/class-9/maths/ganita-manjari-chapter-2/