Lines And Angles

Front 1

point

Back 1

simply a location

We name it using a capital letter

Front 2

line

Back 2

made up of points and has no thickness of width

It always has an arrow at each end.

We name it using 2 points on the line.

Front 3

line segment

Back 3

A piece of line with two end points.

Front 4

colinear

Back 4

points on the same line

Front 5

plane

Back 5

a flat surface made up of points

We name it using 3 points on the plane.

Front 6

coplanar

Back 6

points and/or lines that lie on the same plane

Front 7

congruent

Back 7

segments or angles that have the same measure

Front 8

midpoint

Back 8

the point halfway between the endpoints of the segment

Front 9

ray

Back 9

part of a line with on end point . A ray extends indefinitely in one direction . ( has one point in one end and arrow on the other )

Front 10

angle

Back 10

formed by 2 noncollinear rays

Front 11

rays

Back 11

the sides of an angle

Front 12

vertex

Back 12

the common endpoint of an angle

Front 13

right angle

Back 13

an angle that measures exactly 90°

Front 14

acute angle

Back 14

an angle that measures less than 90°

Front 15

obtuse angle

Back 15

an angle that measures greater than 90°

Front 16

angle bisector

Back 16

a line or ray that divides an angle into 2 congruent angles

Front 17

adjacent angles

Back 17

two angles that share a common side. they are formed by intersecting lines are supplementary that have the sum of 180 degrees

Front 18

vertical angles

Back 18

when two lines intersect, four angles are formed. two angles that are opposite to each other are called vertical angles.

Front 19

complementary angles

Back 19

two angles whose measures have a sum of 90

Front 20

supplementary angles

Back 20

two angles whose measures have a sum of 180

Front 21

perpendicular lines

Back 21

lines that form right angles

Front 22

Straight angle

Back 22

straight line that measures 180 degrees

Front 23

Parallel Lines

Back 23

Two lines that never meet .