Geometry Chapter 1: Points, Lines, Planes, 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

colinear

Back 3

points on the same line

Front 4

plane

Back 4

a flat surface made up of points

We name it using 3 points on the plane.

Front 5

coplanar

Back 5

points and/or lines that lie on the same plane

Front 6

space

Back 6

a boundless, three-dimensional set of all points (contain lines and planes)

Front 7

segment

Back 7

a finite portion of a line

It can be measured because it has two endpoints (unlike a line!)

Front 8

congruent

Back 8

segments or angles that have the same measure

Front 9

midpoint

Back 9

the point halfway between the endpoints of the segment

Front 10

segment bisector

Back 10

any segment, line or plane that intersects a segment at its midpoint

Front 11

ray

Back 11

part of a line

Front 12

angle

Back 12

formed by 2 noncollinear rays

Front 13

rays

Back 13

the sides of an angle

Front 14

vertex

Back 14

the common endpoint of an angle

Front 15

right angle

Back 15

an angle that measures exactly 90°

Front 16

acute angle

Back 16

an angle that measures less than 90°

Front 17

obtuse angle

Back 17

an angle that measures greater than 90°

Front 18

angle bisector

Back 18

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

Front 19

adjacent angles

Back 19

two angles that lie in the same plane, have a common vertex, and a common side, but no common interior points

Front 20

vertical angles

Back 20

two nonadjacent angles formed by two intersecting lines

Front 21

linear pair

Back 21

a pair of adjacent angles whose noncommon sides are opposite rays

Front 22

complementary angles

Back 22

two angles whose measures have a sum of 90

Front 23

supplementary angles

Back 23

two angles whose measures have a sum of 180

Front 24

perpendicular lines

Back 24

lines that form right angles

Front 25

polygon

Back 25

a closed figure formed by a finite number of coplanar segments such that:
(1) the sides that have a common endpoint are noncollinear, and
(2) each side intersects exactly two other sides, but only at their endpoints.

Front 26

concave polygon

Back 26

a polygon such that there is a line containing a side of the polygon that also contains a point of the interior of the polygon

Front 27

convex polygon

Back 27

a polygon such that there is no line containing a side of the polygon that also contains a point of the interior of the polygon.

Front 28

n-gon

Back 28

a polygon with n sides.

Front 29

regular polygon

Back 29

a convex polygon with all sides congruent and all angles congruent.

Front 30

perimeter

Back 30

the sum of the lengths of the sides of a polygon

Front 31

distance formula
(number line)

Back 31

the distance between two points on a number line

Front 32

distance formula
(coordinate plane)

Back 32

the distance between two points on a coordinate plane

Front 33

midpoint formula
(number line)

Back 33

Front 34

midpoint formula
(coordinate plane)

Back 34

Front 35

midpoint formula
(coordinate plane)

Back 35

Front 36

names of polygons

number of sides:
3, 4, 5, 6, 7, 8, 9, 10, 12, & n

Back 36