In angles and lines, Line is a set of points or a line is made of by using infinite number of points. The following figure shows a line. A line is a one-dimensional figure and has no width or height. A line has only length.

A line is denoted in two ways as shown above.

- If we take two points on the line then these points should be in capital, like AB or BA.
- If we want a line to denote by a single letter, it should be a small cap.

**Line Segment:** A line segment is the set of points consisting of A, B, and all points between them. A line segment is written AB or BA

**Ray:** A ray is a line which has only one direction.

## Angles Geometry

When two rays have a common end point, then they form an angle.

The angle formed by the rays AB and AC as shown in the following figure and is denoted by the *L*BAC or *L*CAB.

## Parallel Lines and Angles

- If an angle is 28° less than its complement, find its measurement.
- If an angle is 30° more than one half of its complement, find the measurement of the angle.
- If an angle is 10 ° less than one half of its complement, find the measurement of the angle.
- If the angles (2x – 10)
^{o}and (x – 5)^{o}are complementary angles, find x. - In the following figure find the value of y.

6. In the following figure,find the values of x and y and then show that AB||CD.

7. Two supplementary angles are in the ratio 4:5. Find the angles.

** **

8. An angles in equal to 8 times its complement. Determine its measure.

9.** **In the following figure OA and OB are opposite rays:

10.** **If the complement of an angle is equal to the supplement of the thrice of it. Find the measure of the angle.

11. If the supplement of an angle is two-tired of itself. Determine the angle and its supplement.

12.** **An angles is 14^{o} more then its complementary angle. What is its measure?

13.** **In Fig. POR and QOR form a linear pair. If a – b = 80, find the value of a and b.