# NCERT Solutions for Class 7 Maths Chapter 10 Exercise 10.3

NCERT Solutions for Class 7 Maths Chapter 10 Exercise 10.3 (Ex. 10.3) Practical Geometry in PDF file format free to download or use online for session 2020-2021. If someone is facing problem to understand solutions through PDF, use videos solution.

In class 7 math exercise 10.3, there are only three questions. In each question two sides and an angle is given to form a triangle using ruler and compass.## Class 7 Maths Chapter 10 Exercise 10.3 Solution

Class: 7 | Mathematics |

Chapter: 10 | Practical Geometry |

Exercise: 10.3 | Videos and PDF Solutions |

### CBSE NCERT Class 7 Maths Chapter 10 Exercise 10.3 Solution in Hindi and English Medium

### Class 7 Maths Chapter 10 Exercise 10.3 Solution in Videos

#### l. SSS (Three Sides) Triangle Congruency

To construct a triangle when three sides of it are given. In order to draw a triangle with sides of given lengths, it is necessary that the sum of any two sides must be greater than the third side, Otherwise, the construction of the triangle would be impossible.

Example:

Construct a triangle ABC in which BC = 6.2 cm, AB = 5 cm and AC = 4.3 cm.

Construction: First we draw a rough sketch of triangle ABC, Then, we draw triangle ABC in following steps:

##### Steps of construction:

1. Draw a line segment BC = 6.2 cm.

2. With B as centre and radius 5 cm, draw an arc.

3. With C as centre and radius 4.3 cm, draw another arc, cutting the previous arc at A.

4. Join AB and AC. Then, Triangle ABC is the required triangle.

##### Construct a triangle PQR in which PQ = 5.3 cm, PR = 5 cm and QR = 3.8 cm.

First we draw a rough sketch of triangle PQR. Then, we draw triangle PQR in following steps:

Steps of construction:

1. Draw a line segment PQ = 5.3 cm.

2. With P as centre and radius 4.6 cm, draw an arc.

3. With Q as centre and radius 3.8 cm, draw another arc, cutting the previous arc at R.

4. Join PR and QR. Then, triangle PQR is the required triangle.

#### Properties of triangle

(i) The sum of all three interior angles of a triangle is equal to 180 degrees.

(ii) The measurement of the exterior angle of a triangle is equivalent to the addition of the opposite interior angles.

(iii) The sum of the length of any two sides of a triangle is always greater than the third side of a triangle.

##### What is needed to construct a triangle?

To Construct a Triangle:

(i) Two Angles and One Side, or.

(ii) One Angle and Two Sides, or.

(iii) Three Sides.

##### How do you construct a triangle step by step?

Constructing triangles:

(i) Draw one side of the triangle using a ruler. It is often easier to start with the longest side.

(ii) Set the compass width to 5 cm. Draw an arc 5 cm away from point A.

(iii) Set the compass width to 3 cm. Draw an arc from point B.

(iii) Use your ruler to join points A and B to the point where the arcs intersect (C).

##### What are types of triangle?

Types of triangles:

(i) Acute triangle: An acute angle triangle is a triangle in which all three interior angles are less than 90 degrees.

(ii) Obtuse triangle: An obtuse triangle is a triangle in which one of the interior angles is more than 90 degrees.

(iii) Right Triangle: one angle is 900

(iv) Isosceles triangle: Two sides and two angles are equal.

(v) Equilateral triangle: All three sides and three angles are equal.

(vi) Scalene Triangle: A scalene triangle is a triangle in which all three sides have different lengths. Also the angles of a scalene triangle have different measures.