# Class 7 Maths Chapter 6 Exercise 6.1 Pdf Notes NCERT Solutions

Class 7 Maths Chapter 6 The Triangles And Its Properties Exercise 6.1 pdf notes:-

**Exercise 6.1** Class 7 maths Chapter 6 Pdf Notes:-

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## Ncert Solution for Class 7 Maths Chapter 6 The Triangles And Its Properties Exercise 6.1 Tips:

INTRODUCTION

A triangle, you have seen, is a simple closed curve made of three line segments. It has three vertices, three sides and three angles.

You know how to classify triangles based on the (i) sides (ii) angles.

(i) Based on Sides: Scalene, Isosceles and Equilateral triangles.

(ii) Based on Angles: Acute-angled, Obtuse-angled and Right-angled triangles.

TRY THESE

- Write the six elements (i.e., the 3 sides and the 3 angles) of ∆ABC.
- Write the:

(i) Side opposite to the vertex Q of ∆PQR

(ii) Angle opposite to the side LM of ∆LMN

(iii) Vertex opposite to the side RT of ∆RST

THINK, DISCUSS AND WRITE

- How many medians can a triangle have?
- Does a median lie wholly in the interior of the triangle? (If you think that this is not

true, draw a figure to show such a case).

ALTITUDES OF A TRIANGLE

Make a triangular shaped cardboard ABC. Place it upright on a

table. How ‘tall’ is the triangle? The height is the distance from

vertex A to the base BC

From A to BC , you can think of many line segments. Which among them will represent its height?

The height is given by the line segment that starts from A,

comes straight down to BC, and is perpendicular to BC .

This line segment AL is an altitude of the triangle.

An altitude has one end point at a vertex of the triangle and

the other on the line containing the opposite side. Through each

vertex, an altitude can be drawn.

THINK, DISCUSS AND WRITE

- How many altitudes can a triangle have?
- Will an altitude always lie in the interior of a triangle? If you think that this need not be

true, draw a rough sketch to show such a case. - Can you think of a triangle in which two altitudes of the triangle are two of its sides?
- Can the altitude and median be same for a triangle?

Do This

Take several cut-outs of

(i) an equilateral triangle (ii) an isosceles triangle and

(iii) a scalene triangle.

Find their altitudes and medians. Do you find anything special about them? Discuss it

with your friends.