Page 76 - Start Up Mathematics_6
P. 76
Distance Between Two Parallel Lines
The distance between two parallel lines is the same everywhere.
Ray
A ray is the part of a line having one fixed end point and extending endlessly in the other direction.
A ray denoted by OP is shown below:
O P
Examples of rays
1. Sun rays 2. Rays of light from an electric bulb
Properties of rays G
F H
1. Infinite number of rays can be drawn from a E A
given point.
D B
C
2. One and only one ray can be drawn beginning A
at O and passing through a given point A. O
3. Two rays OA and OB having the same initial point O
and forming a line are known as opposite rays. B O A
Plane
A plane is defined as a smooth flat surface which extends indefinitely in all directions.
Examples of parts of planes:
1. Surface of a smooth wall 2. Surface of a floor in a room
Geometrically, a plane extends indefinitely in all the directions. Therefore, representing a plane
on paper is not possible. A rectangle or a parallelogram represents a part of a plane. A plane is
represented by taking any three non-collinear points on it.
68
