Basic Geometry

Basic geometry definitions are given below. Learn them.

Point: A point is a mark of position. It has neither length nor width nor thickness and occupies no space. It shows the exact location.

Line : A line is a collection of points going endlessly In both directions along a straight path. It has no endpoints.

Line Segment: A line segment is part of a line. It has two endpoints.

Ray: A ray is a part of a line. It has one endpoint and goes on endlessly in one direction.

Angle: When two rays have a common endpoint, they form an angle

Right Angle:   A 90 ˚ angle is called right angle.

Acute Angle: A angle that is smaller than a right angle is called acute angle. It is more than 0 ˚ but less than 90˚.

Obtuse Angle: A angle that is bigger than a right angle is called obtuse angle. It is more than 90˚ but less than 180˚.

Adjacent Angles: Two angles are said to be adjacent if they have a common vertex, one common arm and the other arms of the angles are on the opposite sides of the common arm

Straight Angles: An angle whose sides lie in opposite direction from the vertex in the same straight line is called straight angle. It measures 180˚.

Complementary Angles: Two angles are said to be complementary if their sum is 90˚.

Supplementary Angles: Two angles are said to be complementary if their sum is 180˚.