Geometry Semester 1

Front 1

point

Back 1

a position in space

Front 2

line

Back 2

an infinite continuous set of points extending in opposite directions forming a straight path

Front 3

plane

Back 3

a flat surface containing a set of points extending infinitely in all directions

Front 4

collinear

Back 4

points that lie on the same line

Front 5

coplanar

Back 5

points that lie on the same plane

Front 6

ray

Back 6

the part of a line that consists of a point, called an endpoint, and the set of points on one side of the endpoint

Front 7

line segment

Back 7

a part of a line that consist of two different points on the line, called endpoints, and the set of points on the line that is between them. it has a definite length

Front 8

postulate

Back 8

a statement that is assumed to be true without proof

Front 9

theorem

Back 9

a statement that can be proven by deductive reasoning

Front 10

congruent

Back 10

two figures that have the same size and shape

Front 11

angle

Back 11

the union of two rays that share a common endpoint

Front 12

vertex of an angle

Back 12

the intersection of two rays of an angle

Front 13

bisector

Back 13

a line, ray, or lene segment that divides an angle or line segment into two parts that have the same measure

Front 14

adjacent angles

Back 14

two coplanar angles that share a common vertex and a common side but have no interior points in common (do not overlap)

Front 15

supplementary angles

Back 15

two angles whose degree measures add up to 180 degrees

Front 16

complementary angles

Back 16

two angles whose degree measures add up to 90 degrees

Front 17

straight angle

Back 17

any angle whose degree measure is 180 degrees

Front 18

midpoint

Back 18

the point that divides a line segment into two congruent segments

Front 19

perpendicular lines

Back 19

two lines that intersect to form right angles

Front 20

perpendicular bisector

Back 20

a line that is perpendicular to a line segment intersecting the line segment at its midpoint

Front 21

polygon

Back 21

a closed figure formed by coplanar line segments that are joined at their midpoints.

Front 22

regular polygon

Back 22

a polygon whose sides and angles are all congruent

Front 23

triangle

Back 23

a polygon that has exactly three sides

Front 24

acute triangle

Back 24

a triangle whose angles are les than 90 degrees

Front 25

right triangle

Back 25

a triangle with one right angle and two acute angles

Front 26

hypotenuse

Back 26

the side of a triangle that is opposite the right angle

Front 27

leg

Back 27

the two sides of a right triangle that form the right angle, or the two congruent sides of an isosceles triangle

Front 28

obtuse triangle

Back 28

a triangle that has one angle that is greater than 90 degrees.

Front 29

equilateral triangle

Back 29

a triangle whose sides and angles are congruent

Front 30

isosceles triangle

Back 30

a triangle with two congruent sides

Front 31

base angles

Back 31

the angles in an isoscles triangle that are opposite the legs

Front 32

vertex angle

Back 32

the angle in an isosceles triangle that is formed by the two congruent sides. it is opposite the base

Front 33

scalene triangle

Back 33

a triangle with no congruent sides or angles

Front 34

altitude of a triangle

Back 34

the line segment drawn from the vertex of a triangle that is perpendicular to the opposite side

Front 35

median of a triangle

Back 35

the line segment drawn from a vertex of a triangle to the midpoint of the opposite side

Front 36

quadrilateral

Back 36

a four sided polygon

Front 37

parallelogram

Back 37

a quadrilateral whose opposite sides are parallel

Front 38

rectangle

Back 38

a parallelogram consisting of four right angles

Front 39

rhombus

Back 39

a parallelogram with four congruent sides

Front 40

square

Back 40

a parallelogram containing four congruent sides and four right angles

Front 41

trapezoid

Back 41

a quadrilateral with only one pair of parallel sides

Front 42

isosceles trapezoid

Back 42

a trapezoid whose nonparallel sides are congruent

Front 43

alternate interior angles

Back 43

a pair of angle with differnt vertices that lie between two lines and on opposite sides of a transversal

Front 44

transversal

Back 44

a line that intersects two other lines in two different points

Front 45

vertical angles

Back 45

the opposite pairs of congruent angles that are formed when two lines intersect

Front 46

corresponding angles

Back 46

a pair of angles consisting of one iterior angle and one exterior angle with different vertices on the same side of a transversal.

Front 47

alternate exterior angles

Back 47

a pair of angles with different vertices that lie outside two lines and on opposite sides os a transversal

Front 48

parallel lines

Back 48

lines that lie on the same plane and do not intersect