Introduction to lines and angles — lesson. Mathematics CBSE, Class 7.

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Let us recall what a line, a line segment, a ray and an angle is.

Line:

If two points are extended endlessly in both directions in a straight path, a line is drawn.

In the figure, the two points

$P$ and

$Q$ are extended endlessly in both directions to get a line

$PQ$ .

The line

$PQ$ is denoted as

$\overleftrightarrow{PQ}$ .

Line Segment:

The line connecting of two end points is a line segment.

In the figure, the line connects the two points end

$P$ and

$Q$ to form a line segment.

The line segment

$PQ$ is denoted as

$\overline{PQ}$ .

Ray:

A line consisting of one end point or a starting point is a ray.

In the figure, the line

$PQ$ extends endlessly from a starting point

$P$ to form a ray.

The ray

$PQ$ is denoted as

$\overrightarrow{PQ}$ .

Angle:

When two line segments or lines intersect with each other, they form an angle.

In the figure, the lines

$\overleftrightarrow{OA}$ and

$\overleftrightarrow{OB}$ intersect at

$O$ to form an angle

$AOB$ .

The angle

$AOB$ is represented as

$\angle AOB$ .

Important!

Click here! To recall the types of angles.

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1. Introduction to lines and angles