What is a line?
A line can be defined as a type of geometric figure which can extend in both directions. It has got length but it has no width. A line is constructed of an endless number of points. A line is infinite and it has no ends on both sides of it. It is a one-dimensional figure.
Lines in Math’s
In geometry, the concept of line or straight line was pioneered by ancient mathematicians to denote straight objects which have very minute width and depth. For example:
A line in the plane is said to be the set of points whose coordinates fulfill a given linear equation in analytic geometry, well-defined from the set of points which lie on it in incidence geometry.
Types of lines
There are various types of lines used in geometry. They are the basis of geometry. There are basically two types of line. They are:
- Straight line
- Curved line
Straight lines are further divided into horizontal lines (sleeping lines), vertical lines (sleeping lines) and oblique lines (slanting lines). The equation of straight is written as:
- Horizontal line
Definition: A line which is parallel to x-axis is known as a horizontal line. A horizontal line goes ahead parallel to the x-axis. It does not touch any point on the x-axis.
Examples of horizontal lines
The red and white stripes in the flag are examples of horizontal lines. Other real-life examples are the steps on the staircase, planks on the railway tracks.
- Vertical Line
Definition: A line which is parallel to y-axis is known as vertical line. It moves straight up and down, parallel to the y-axis of the coordinate plane.
Some real-life examples of vertical lines are the steel rails in a fence, a row of tall trees on a highway, electric poles placed on the roads.
Other types of lines
When two or more lines are used together, they make different types of lines like parallel lines, perpendicular lines, and transversal lines as given below.
- Parallel lines
When two lines that run together and are separated by the same distance and do not clash with each other are called as parallel lines, irrespective of the length of the lines. Curves that do not meet each other or intersect with each other and maintain a fixed minimum distance are said to be parallel. Two straight lines in a plane which do not intersect with each other at any point are said to be parallel.
The symbol11 is used to denote parallel lines.
Some real-life examples of parallel lines are railway tracks, walls of buildings, stack of identical notebooks like in school classrooms, collection of same-sized papers etc.
- Intersecting lines
When two non-parallel lines meet at a point, those lines are called intersecting lines. Intersecting lines are those two lines which share exactly one point. This shared point is known as the point of intersection.
Real-life example of intersecting lines are the scissors. The two blades of the scissors intersect with each other to perform work effectively.