Summary

Summary

● A line extends along both directions without end.

● A line segment has two end points.

● Parallel lines never meet.

● When two lines meet they are called intersecting lines.

● When two rays have common starting point, they form an angle at that point.

● We measure angles using protractor.

● An angle whose measure is less than 90º is called an acute angle.

● An angle whose measure is exactly 90º is called a right angle.

● An angle whose measure is greater than 90º is called an obtuse angle.

● When the two rays or lines coincide, they are said to make angle zero, that is 0º.

● Two angles are complementary when they add up to 90º.

● Two angles are supplementary when they add up to 180º.

● Given any two points there is a unique line passing through them.

● When three points lie on a line, they are said to be collinear.

● When two lines meet each other at 90°s at the point of intersection, they are called perpendicular lines.

● When three or more lines pass through the same point, they are said to be concurrent. That point is called the Point of Concurrency.