RS Aggarwal Chapter 13 Class 9 Maths Exercise 13.2 Solutions: In earlier chapters, the diagrams, which were necessary to prove a theorem or solving exercises were not necessarily precise. They were drawn only to give you a feeling for the situation and as an aid for proper reasoning. However, sometimes one needs an accurate figure, for example – to draw a map of a building to be constructed, to design tools, and various parts of a machine, to draw road maps etc. To draw such figures some basic geometrical instruments are needed.

Normally, all these instruments are needed in drawing a geometrical figure, such as a triangle, a circle, a quadrilateral, a polygon, etc. with given measurements. But a geometrical construction is the process of drawing a geometrical figure using only two instruments – an ungraduated ruler, also called a straight edge and a compass. In construction where measurements are also required, you may use a graduated scale and protractor also. In this chapter, some basic constructions will be considered. These will then be used to construct certain kinds of triangles.

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## Download RS Aggarwal Chapter 13 Class 9 Maths Exercise 13.2 Solutions

## Important Definition for RS Aggarwal Chapter 13 Class 9 Maths Ex 13b Solutions

**Basic Constructions****Some Constructions of Triangles**

- Use only ruler and compass while drawing constructions.
- Protractor may be used for drawing non-standard angles.
- Construction of bisector of a Line segment using compass – Draw a line segment. With both the points of the line segment as centre and taking the radisu of more than half of the measure of line segment, draw the arcs on both sides, which cuts at two points on opposite sides. Join these two points. This line is the required bisector.
- Construction of the bisector of a given angle – For bisecting an angle means drwing a ray in the interior of the angle, with its initial point at the vertex of the angle such that it divides the anlge into two equal parts.
- Construction of some standard angles such as 60o, 30o, 90o, 45o, 120o, etc.
- Constructions of a triangle is possible if its base, a base angle and the difference of the other two sides are given.
- Construction of a triangle when its base, sum of the other two sides and one base angle are given.
- Constructions of a triangle is possible if its perimeter and two base angles are given.

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