The tip of a nail or pin can be taken as a physical model of a dot. In reality,a dot in geometry is even smaller than the tip of a nail or pin.

There are two types of dots 1) Collinear 2) non-collinear.

1)

Dots A, B,C and D which lie on line l are collinear . Line l is known as the

2)

The dots P,Q and R are non-collinear .

i) A dot has no length and no width.

ii) A dot has thickness.

iii) An infinite number of dots lie on a circle.

iv) Non-collinear dots lie on straight line.

v) A dot shows the exact location.

i) True

ii) False. ( A dot has no thickness.)

iii) True

iv) False ( Non-collinear dots do not lie on straight line.)

v) True

Q.2 P and Q, Q and R & P and R are collinear.

P,Q, R are non collinear.

• Point

• Lines

• Angles

• Lines and Angles

• Complementary angles

• Supplementary angles

• Vertically Opposite Angles

• Linear Pair Angles

• Adjacent Angles

• Parallel Lines

• Solved Problems on Intersecting Lines

• Solved Problems on Parallel Lines