1. Presentation on ANGLES BY ADITI JAIN KUJA VI-D

2. CONTENTS WHAT IS AN ANGLE? NAMING AN ANGLE TYPES OF ANGLES PAIRS OF ANLGES

3. WHAT IS AN ANGLE??? When two non-collinear rays join from a common end point (origin) an angle is formed. Ray BA A Common endpoint B B B C Common endpoint is called the VERTEX OF ANGLE .B is the vertex of angle ABC AB and BC are the two non collinear rays. Ray AB and BC are called the ARMS of the angle.

4. 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. A C B ABC OR CBA FOR EXAMPLE : We may also name this angle only by the single letter of the vertex, fr example B .

5. TYPES OF ANGLES ACUTE ANGLE OBTUSE ANGLE RIGHT ANGLE STRAIGHT ANGLE REFLEX ANGLE ZERO ANGLE

6. ACUTE ANGLE An acute angle is an angle measuring between 0 and 90 degrees. Example:

7. OBTUSE ANGLE An obtuse angle is an angle measuring between 90 and 180 degrees. Example:

8. RIGHT ANGLES A right angle is an angle measuring 90 Degrees. Example:

9. ZERO ANGLE An angle measuring 0 is called a zero angle . Example: C A B Rays AB and AC are said to be at zero angle with each other.

10. REFLEX ANGLE An angle whose measure is more than 180( deg) but less than 360(deg) is called a reflex angle. Example: o A AOB Angle Is called as the REFLEX ANGLE B

11. STRAIGHT ANGLE An angle whose measure is 180(deg) is called as a straight angle. Example: A B C AOB is called as STRAIGHT ANGLE .

12. PAIRS OF ANGLES COMPLEMENTARY PAIRS SUPPLEMENTARY PAIRS ADJACENT ANGLES VERTICALLY OPPOSITE ANGLES LINEAR PAIR

13. COMPLEMENTARY ANGLES Two angles whose sum is 90(deg) are called as complementary angles. Here AOB = 40 and BOC = 50 B C 50 AOB + BOC = 90 40 O A The two angles are said to be complementary to each other.

14. SUPPLEMENTARY ANGLES Two angles whose sum is 180(deg) are called as supplementary angles. R Here PQR= 50 and RQS = 130 130 50 PQR + RQS = 180 Hence the two angles are said to be supplementary to each other. s p Q

15. ADJACENT ANGLES Two non overlapping angles are said to be adjacent angles if they have a common vertex , a common arm, and other two arms lying on opposite sides of this common arm, so that their interiors do not overlap. B C AOB and BOC are the adjacent angles. O

16. VERTICALLY OPPOSITE ANGLES Two angles formed by two intersecting lines having no common arm are called vertically opposite angles. A D O Angles AOD and COB vertically opposite Similarly angles AOC and DOB are vertically opposite angles B C

17. LINEAR PAIR Two adjacent angles are said to form a Linear pair if their sum is 180. A Sum of angle AOB and angle AOC is 180. hence they are called as LINEAR PAIR B C

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