Bombay Cambridge Gurukul

1. Bombay Cambridge Gurukul Bombay Cambridge Gurukul STD. : VI MATHEMATICS

2. Contents • Test Yourself - 1 • Angles in daily life • Congruent angles • Pairs of angles: Types • What is an angle? • Test Yourself - 2 • Naming an angle • Pairs of angles formed by a transversal • Measurement of angle • Types of angle: Right angle • Obtuse angle • Acute angle • Straight angle • Test Yourself - 3

3. Angles In Daily Life If we look around us, we will see angles everywhere.

4. A B C Ray BAand rayBCare called thearmsof ABC. What Is An Angle ? When two non-collinear rays join with a common endpoint (origin) an angle is formed. Ray BA B Common endpoint Ray BC Common endpoint is called the vertex of the angle.Bis thevertexof ÐABC. Ray BA and BC are two non-collinear rays

5. Fact: We can also think of an angle formed by rotating one ray away from its initial position.

6. A B C Naming An Angle To name an angle, we name any point on one ray, then the vertex, and then any point on the other ray. For example: ÐABC or ÐCBA We may also name this angle only by the single letter of the vertex, for example ÐB.

7. Measurement Of An Angle Protractor is used to measure and draw angles. Angles are accuratelymeasured in degrees.

8. B A A A B C B B C A C C Types Of Angles There are four main types of angles. Right angle Acute angle Obtuse angle Straight angle

9. Right angle: An angle whose measure is 90 degrees. Straight Angle Right Angle Acute Angle Obtuse Angle

10. Examples Of Right Angle

11. Obtuse angle: An angle whose measure is greater than 90 degrees. Straight Angle Right Angle Acute Angle Obtuse Angle

12. Examples Of Obtuse Angle

13. Acute angle: An angle whose measure is less than 90 degrees. Straight Angle Right Angle Acute Angle Obtuse Angle

14. Examples Of Acute Angle

15. Straight angle: An angle whose measure is 180 degrees. Straight Angle Right Angle Acute Angle Obtuse Angle

16. Examples Of Straight Angle

17. The End Created by: The Department of Research Bombay Cambridge Gurukul