NCERT Solutions for Class 9 Maths Chapter 7: Triangles

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The NCERT Solutions for class 9 Maths Chapter 7 Triangles are included in the article below. A triangle is a closed shape with three angles, three sides, and three vertices. It has two basic formulas that help us to determine its area and perimeter.

Class 9 Maths Chapter 7 Triangles belong to Unit 4 Geometry which has a weightage of 27 marks in the Class 9 Maths Examination. Class 9 Maths Chapter 7 has the following important concepts:

Download: NCERT Solutions for Class 9 Mathematics Chapter 7 pdf

NCERT Solutions for Class 9 Mathematics Chapter 7

The Chapter 7 Class 9 Maths are given below:

Important Topics in Class 9 Maths Chapter 7 Triangles

Important Topics in Class 9 Maths Chapter 7 Triangles are elaborated below:

Area of Triangles

The area of a triangle is the space confined within the three sides of a triangle. For calculating its area, the base length and the height of the triangle are required.

Example: What is the formula to determine the area of a triangle?

Solution: The formula to determine the Area of a Triangle is:
Area of triangle = ½ (base x height) = ½ b x h

Perimeter of Triangles

The perimeter of a respective triangle can be defined as the sum of three sides of the triangle. For example, if a triangle has sides ABC, then the perimeter of it would be (AB + BC + AC).

Perimeter of Scalene Triangle: A + B + C
Perimeter of Iosceles Triangle: 2A + B
Perimeter of Equilateral Triangle: 3A

Congruency of Triangles

If two triangles have the same shape and size, then they are found congruent to one another.

Example: List all the followed criteria for congruency in a triangle.

Solution: The criteria of conguency in Triangles are:

SSS (side-side-side) congruency
SAS (side-angle-side) congruency
ASA (angle-side-angle) congruency
AAS (angle-angle-side) congruency
RHS (right angle-hypotenuse-side) congruency

NCERT Solutions for Class 9 Maths Chapter 7 Exercises:

The detailed solutions for all the NCERT Solutions for Triangles under different exercises are:

Also Read:

Unit Related Topics
Triangle Theorems	Pythagoras Theorem	Questions on Triangles
Mid Point Theorem	Isosceles Triangle	Class 9 Maths Chapter 7 Triangles MCQs
Sides of a Triangle	Similar Figures	Properties of Triangles

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Maths Important Formulas	Maths MCQs	Comparison Articles in Maths
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CBSE X Related Questions

1.
Assertion (A) : If probability of happening of an event is \(0.2p\), \(p>0\), then \(p\) can't be more than 5.
Reason (R) : \(P(\bar{E}) = 1 - P(E)\) for an event \(E\).
- Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
- Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
- Assertion (A) is true, but Reason (R) is false.
- Assertion (A) is false, but Reason (R) is true.
View Solution
2.
A conical cavity of maximum volume is carved out from a wooden solid hemisphere of radius 10 cm. Curved surface area of the cavity carved out is (use \(\pi = 3.14\))
- \(314 \sqrt{2}\) \(\text{cm}^{2}\)
- \(314\) \(\text{cm}^{2}\)
- \(\frac{3140}{3}\) \(\text{cm}^{2}\)
- \(3140 \sqrt{2}\) \(\text{cm}^{2}\)
View Solution
3.
An ice-cream cone of radius \(r\) and height \(h\) is completely filled by two spherical scoops of ice-cream. If radius of each spherical scoop is \(\frac{r}{2}\), then \(h : 2r\) equals
- \(1 : 8\)
- \(1 : 2\)
- \(1 : 1\)
- \(2 : 1\)
View Solution
4.
For any natural number n, \( 5^n \) ends with the digit :
- 0
- 5
- 3
- 2
View Solution
5.
Prove that \(2 + 3\sqrt{5}\) is an irrational number given that \(\sqrt{5}\) is an irrational number.
View Solution
6.
If \(PQ\) and \(PR\) are tangents to the circle with centre \(O\) and radius \(4 \text{ cm}\) such that \(\angle QPR = 90^{\circ}\), then the length \(OP\) is
- \(4 \text{ cm}\)
- \(4\sqrt{2} \text{ cm}\)
- \(8 \text{ cm}\)
- \(2\sqrt{2} \text{ cm}\)
View Solution

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NCERT Solutions for Class 9 Maths Chapter 7: Triangles

NCERT Solutions for Class 9 Mathematics Chapter 7