CBSE · Class 6-12

Class 6 · Ganita Prakash

Unit 2 · Class 6Ganita Prakash

Lines and Angles

Points, lines, rays, and how angles are measured and classified.

Lessons

4 concepts

1
Basic Elements
In geometry we start with the smallest object — a point. Combining points gives lines, rays, and segments. Two lines can be parallel or intersecting.
2
Measuring Angles
Use a protractor: align its centre on the vertex and the 0° line along one arm. Read where the other arm crosses. Angles are in degrees (°). Full turn = 360°.
3
Types of Angles
Acute: less than a right angle. Right: exactly 90°, formed by perpendicular lines. Obtuse: 90°-180°. Straight: 180°. Reflex: 180°-360°.
4
Angle Relationships
Complementary: sum to 90°. Supplementary: sum to 180°. Vertically opposite angles are equal.

Skills to practise

Skill · medium

Lines and Angles — Practice