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| Summary |
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| Point |
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| It is an exact location. It is a fine dot which has neither length nor breadth nor thickness but has position i.e., it has no magnitude. It is denoted by capital letters A, B, C, O etc. |
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| Line segment |
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The straight path joining two points A and B is called a line segment  |
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| Ray |
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| A line segment which can be extended in only one direction is called a ray. |
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| Line |
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| When a line segment is extended indefinitely in both directions it forms line. |
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| Collinear points |
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| If two or more points lie on the same line, then they are called collinear points. |
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| Intersecting lines |
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| Two lines having a common point are called intersecting lines. The common point is known as the point of intersection. |
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| Concurrent lines |
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| If two or more lines intersect at the same point, then they are known as concurrent lines. |
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| Plane |
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| A plane is a surface such that every point of the line joining any two points on it, lies on it. |
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- The line containing any two points in a plane lies wholly in that plane.
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- An angle has only one and only one bisector.
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- Through any point outside a line, one and only one perpendicular can be drawn to the given line.
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- A segment has one and only one mid point.
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- Linear pair postulate: If a ray stands on a line, then the sum of the two adjacent angles so formed is 180o.
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| Angles |
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| When two straight lines meet at a point they form an angle. |
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| Types of Angles |
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| Complementary and Supplementary angles |
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| If the sum of the two angles is one right angle (i.e., 90o), they are called complementary angles. |
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| Supplementary angles |
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| Two angles are said to be supplementary, if the sum of their measures is 180o. |
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| Vertically opposite angles |
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| When two straight lines intersect each other at a point, the pairs of opposite angles so formed are called vertically opposite angles. |
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