# Types of triangles based on angles

From Karnataka Open Educational Resources

A triangle can be drawn with different measures of angles which also determine the kind of triangle formed.

## Contents

### Objectives

Recognize the triangles based on the measures of the sides

### Estimated Time

20 minutes

### Prerequisites/Instructions, prior preparations, if any

Prior knowledge of point, lines, angles, elements of triangle

### Materials/ Resources needed

- Digital : Computer, geogebra application, projector.
- Non digital : Worksheet and pencil.
- Geogebra files : “
**Types of triangle by angle.ggb**”

Download this geogebra file from this link.

### Process (How to do the activity)

- Identify the angle types in the triangle.
- Can the angles in the triangle be of different type – obtuse or right angle.
- Establish the types of triangles based on the types of angles that form the triangle – when all angles are acute angles, when one of the angle is a right angle and when one of the angle is obtuse angle.
- Is it possible to have a triangle with two right angle or two obtuse angle. Why or why not?
- What kind of a triangle is formed when all the angles are equal? For what measure of the angle such a triangle is formed?
- Can a triangle be formed with a reflex angle.
- Measure the angles for different triangle, recognize the types of angles and conclude the type of triangle.

Observation | Angle 1 measure and
its Type |
Angle 2 measure and
its Type |
Angle 3 measure and
its Type |
What can you say about angles? | Type of triangle formed |
---|---|---|---|---|---|

Triangle 1 | |||||

Triangle 2 | |||||

Triangle 3 |

**Evaluation at the end of the activity**

- Are children able to recognize the types of triangles based on the angles in a triangle.