Class 9 CBSE math notes are provided here to help students overcome the challenges in learning the concepts of constructions. The notes which contain detailed information can be used as a great reference tool for studying productively as well as completing revisions before the exams. Some of the topics that are covered in the construction chapter are;

- Definition of Construction.
- Carrying out some basic constructions and giving reasons as to why these constructions are valid.
- Constructions of a triangle.
- Practice Questions.

## What is Construction?

The construction which is an important part of geometry basically means drawing angles, shapes, and lines in perfection. Constructions are usually carried out using only a ruler, compass and a pencil. As such, in chapter 11 students learn about the steps of drawing the perfect geometrical figures.

### Basic Constructions

**Construction 1:** To construct a given angle.

**Construction 2:** To construct the bisector of a given angle.

**Construction 3: **To construct the perpendicular bisector of a given line segment.

Steps of Construction

**Construction 4:** To construct an angle of 60 degrees.

#### Construction of Triangles

When we talk about the construction of a triangle we usually do not need the dimension and angles. However, there are some key conditions that can be followed when creating a triangle. Some of the conditions are as follows;

#### Important Questions:

- Construct an angle of 90 degrees and justify the construction.
- Construct a triangle PQR in which QR = 5cm, ∠Q = 60° and PR – PQ = 2cm.
- Construct a right triangle whose base is 10cm and the sum of its hypotenuse and another side is 15 cm.

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