# Chapter 11 Perimeter and Area Class 7 Notes Maths

Chapter 11 Perimeter and Area Class 7 Notes Maths provided here will provide a quick glimpse of the chapter and improve the learning experience. It will be make sure that a student has understood the specifics of every chapter in clear and precise manner. You will also findÂ NCERT Solutions for Class 7 Chapter 11 Maths which will help you in improving the marks in the examinations and have edge over your classmates. Through these Revision Notes for Class 7, a student can boost their preparation and assessment of understood concepts.

Squares and Rectangles

â€¢ Perimeter of a regular polygon = number of sides Ã— length of one side

â€¢ Perimeter of a square = 4 Ã— side

â€¢ Perimeter of a rectangle = 2 Ã— (l + b)

â€¢ Area of a rectangle = l Ã— b

â€¢ Area of a square = side Ã— side

Triangles as Parts of Rectangles

â€¢ If we cut the rectangle along its diagonal to get two triangles, then
The area of each triangle = 1/2 (Area of the rectangle)

â€¢ If we take a square and divide it into 4 triangles, then
The area of each triangle = 1/4 (Area of the square)

Area of Parallelogram

â€¢ The area of parallelogram = base Ã— height.

â€¢ Any side of a parallelogram can be chosen as base of the parallelogram. The perpendicular dropped on that side from the opposite vertex is known as height (altitude).

Area of a Triangle

â€¢ The area of triangle = 1/2 Ã— base Ã— height.

â€¢ Are of equilateral triangle =Â âˆš3/4 Ã— (side)2

â€¢ All the congruent triangles are equal in area but the triangles equal in area need not be congruent.

Circle

â€¢ The distance around a circle is known as its circumference.

â€¢ The ratio of circumference and diameter of a circle is a constant and is denoted by it (pi).

â€¢ Approximate value of Ï€ is taken as 22/7 or 3.14.

â€¢ Circumference of a circle of radius r = 2Ï€r

â€¢ Area of a circle of radius r = Ï€r2.

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