Geometric Concepts and Vocabulary

Point

• A point has no dimensions or size.• A point is named by a single letter.

X point X

Line

• A line has 1 dimension, length.

A CB

b = line b or , , , .AB AC BA etc������������������������������������������������������������������ �����

Ray

• A ray is formed from a line by selecting a starting point and then including all points headed in one direction from the starting point.

K

J KJ or KM����������������������������

M

Segment

• A segment is a piece of a line that has a distinct beginning and end at points called endpoints.

• A segment is named by its endpoints in either order with a bar over them. G H I , , not or GI IG GH HI

Angle

• An angle is a figure formed by two rays (the sides) with a common endpoint (the vertex).

K

J

M4

, 4, ,K JKM MKJ

Plane

• A plane has 2 dimensions, length and width.• A plane extends infinitely in both directions.• A plane can be named by 3 noncollinear

points or by a single, cursive (or italic), capital letter.

Q

S

R plane QRS, QRS, SQR, etc.