CBSE Class 7 Maths Revision Notes Chapter 6

H1 – CBSE Class 7 Mathematics Revision Notes Chapter 6 – The Triangle and Its Properties

Class 7 Mathematics covers different chapters. Out of many, one equally important chapter is Chapter 6 – The Triangle and its properties. The chapter comprises several basic concepts which further help in solving questions. With so many formulas and concepts, it is challenging for students to understand the whole chapter in one go. Hence, the subject experts at Extramarks specially crafted the Class 7 Mathematics Chapter 6 Notes to help the candidates understand the rudimentary concepts of “Triangle and its Properties.” 

The notes have been prepared with easy language and simple examples in order to make them easy to understand for students. The students can thus rely on the Class 7 Chapter 6 Mathematics Notes to clear out the concepts and get good marks. To level up the preparation, the experts at Extramarks recommend that students study the NCERT book and also refer to the specially curated Chapter 6 Mathematics Class 7 Notes. To score good marks, clear doubts, and get clarity on the chapter, it is thus important for the candidates to regularly revise the Extramarks Class 7 Mathematics Notes Chapter 6.

H2 – Revision Notes for CBSE Class 7 Maths Chapter 6 – Free PDF Download

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H2 – Access Class 7 Mathematics Chapter 6 – The Triangle and its Properties Notes

Class 7 Mathematics The Triangle and Its Properties – Important Topics

The chapter Triangle and Its Properties do hold very important concepts from examination point of view. All students must understand each concept given in the chapter one by one for better understanding of the complete chapter. Among the important topics in chapter 7 Mathematics, these are the main topics that you must understand in detail and follow the series likewise: 


A triangle consists of three vertices and three edges. This is a basic geometric shape. The letter ABC indicates a triangle formed by vertex A, B, and C.

Type of Triangle Based on Sides:

There are three types of triangles – equilateral, isosceles, and scalene triangle. 

  • Equilateral Triangle:

A triangle with three equal sides is called an equilateral triangle. The area of an equilateral triangle may be computed if the length of one of its sides is known. The height of an equilateral triangle is also referred to as the altitude that separates the triangle into two congruent right-angled triangles. 

  1. Isosceles Triangle:

A pediment or gable may contain an isosceles triangle, which has been a popular adornment since ancient times. An isosceles triangle is with at least two equal-length sides in geometry. There are various definitions of it, with the former form including the equilateral triangle as a specific case, stating that it has exactly two equal sides and the latter form stating that it has at least two equal sides. 

  • Scalene Triangle:

A scalene triangle with all of the sides are different lengths and all angles are different sizes. In a scalene triangle, all the angles add up to 180, according to the angle sum property. There are four properties of scalene triangle: 

  • All the three sides and angles will have varied length and measurements. 
  • There are no parallel sides in the scalene triangle. Furthermore, there is no symmetry in the scalene triangle. 

Property of the Lengths of Sides of a Triangle:

  • Either of the two sides of a triangle are greater than the length of the third side.
  • The distance between any two sides is less than the distance between the third and fourth sides.
  • For assessing whether a triangle can be drawn when all three sides have the same length, this property is significant.

Types of Triangle-based on Angles:

  • Right Angled Triangle: 

A right angled triangle has one of the angles measures 90 degrees. It is formed by its hypotenuse and legs. A right angled triangle’s hypotenuse is opposite the right angle.

  • Obtuse Angled Triangle:

Obtuse angled triangle is a triangle with one angle measured more than 90 degrees. 

  • Acute Angled Triangle:

Acute angled triangle is a triangle with one angle measured less than 90 degrees. 

Pythagoras Theorem

Pythagoras Theorem states that “In a right-angled triangle,  the square of the hypotenuse side is equal to the sum of squares of the other two sides.” Triangles have three sides called perpendicular, base, and hypotenuse. In this case, the hypotenuse is the longest side since it is opposite the 90° angle. A Pythagorean triple is an equation made up of the sides of a right triangle whose positive integer values are squared.

Exterior Angle 

The exterior angle of a triangle is equal to the sum of its internal opposite angles. In the process of making a triangle’s side, an external angle is formed. 

A Property of Exterior Angles:

On measuring the internal opposite angles of a triangle then the sum will be equal to the measure of the triangle’s outer angles. 

The Angle Sum Property of a Triangle:

Angle sum property of a triangle states that on adding all the angles then the sum will be 180 degrees in total. 

Property of the Lengths of Sides of a Triangle:

  • The lengths of either of the triangle’s two sides will be greater than the length of the third side.

  • Any difference in length between two triangle sides is always smaller than the length of the third side.

Benefits of CBSE Class 7 Maths Chapter 6 Revision Notes

There are multiple benefits that you can get with Extramarks class 7 chapter 6 revision notes

  • When it comes to the end-time exam preparation, students need revision notes covering all the concepts of the chapter one by one. 
  • Students can revise all the concepts in one-go without worrying about missing anything. 
  • Extramarks’s Class 7 Maths Chapter 6 Revision Notes are created by subject specialists and experts, so you can rely on them totally without referring to any other third-party concepts.

FAQs (Frequently Asked Questions)

1. What is the Pythagorean theorem?

The square of the hypotenuse of a right triangle is equal to the sum of the squares of the other two sides, according to Pythagoras’ theorem.

2. Can the Pythagorean Theorem be applied to any triangle?

Pythagoras theorem can only pertain to right-angled triangles.

3. What exactly is an obtuse triangle?

An obtuse triangle is one with one angle more than 90 degrees and the total of all three interior angles equaling 180 degrees.

4. Using Pythagoras' theorem, describe the procedures required in determining the sides of a right triangle.

Step 1: To get the sides of a right triangle which are not given, use the Pythagoras theorem formula with the known values.

Step 2: Reduce the number of variables in the equation to obtain the unknown side.

Step 3: Determine the unknown side of the equation.

5. In what kind of questions, pythagoras theorem can be applied?

Pythagoras theorem can be applied in following cases: 

  • When we have to determine whether or not the triangle is right-angled.
  • When we need to determine a square’s diagonal.
  • If we know the lengths of the other two sides of a right-angled triangle, we may compute the length of any side.