Unit 1 and 2 Geometry Vocabulary

point : (one of the three undefined terms of geometry) represents a location; no size or dimension.

line : (one of the three undefined terms of geometry) a straight, continuous arrangement of infinitely many points extending forever in two directions; has infinite length but no width or depth, so it is one-dimensional.

ray : A point on a line, and all the points on the line that lie on one side of the point

angle : two non-collinear rays having a common endpoint. The measure of an angle is the smallest amount of rotation about the vertex from one ray to the other, measured in degrees

compass : a tool used to construct circles

protractor : a tool used to measure the size of an angle in degrees

angle bisector : a ray that has its endpoint at the vertex of the angle and that divides the angle into two congruent angles

collinear : on the same line

obtuse angle : an angle that measures greater then 90 degrees and less than 180 degrees

right angle : an angle that measures exactly 90 degrees

polygon : A closed figure formed by three or more line segments

consecutive sides : two sides in a polygon that share a common vertex

consecutive vertices : two vertices in a polygon that are the endpoints of one side

opposite sides (quadrilateral) : two sides that do not share a vertex

diagonal : a line segment connecting two non-consecutive sides in a polygon

convex polygon : a polygon with no diagonal outside the polygon

regular polygon : a polygon whose sides and angles are all congruent; a polygon which is both equiangular and equilateral

triangle : a polygon with three sides

perpendicular : lines, segments, or rays that meet at 90 degree angles

perpendicular symbol : a symbol that is used to state that two lines are perpendicular