What Have We Discussed?

1.A point determines a location region and is usually denoted by a capital letter.

2. A line segment corresponds to the shortest distance distance longest distance between two points. The line segment joining points say, A and B is denoted by AB.

3. A line is obtained when a line segment like AB is extended on both sides on one side indefinitely; it is denoted by AB or sometimes by a single small letter like l.

4. Two distinct lines meeting at a point are called intersectingparallel lines.

5. Two lines in a plane are said to be parallelintersecting if they do not meet.

6. A raycurve is a portion of line starting at a point and going in one direction endlessly.

7. Any drawing (straight or non-straight) done without lifting the pencil may be called a curveray. In this sense, a line is also a .

8. A simplecurve curve is one that does not cross itself.

9. A curve is said to be closedopen if its ends are joined; otherwise it is said to be openclosed.

10. A is a simple closed curve made up of line segments.

Here, (i) The line segments are the sidesvertex of the polygon.

(ii) Any two sides with a common end point are adjacentvertex sides.

(iii) The meeting point of a pair of sides is called a vertexsides.

(iv) The end points of the same side are adjacentvertex vertices.

(v) The line joining any two non-adjacent vertices is called a diagonalvertex.

11. An angle is made up of two rayssimple starting from a common starting/initial point.

For eg: Two rays OA and OB make ∠AOB (or also called ∠BOA).

12. An angle leads to three divisions of a region: On the angle, the interior of the angle and the exterior of the angle.