Vocabulary

Question 1

collinear

Answer 1

points that lie on the same line

Question 2

coplaner

Answer 2

figures that are in the same plane

Question 3

space

Answer 3

set of all points

Question 4

endpoint

Answer 4

a single point indicating where a line segment or ray ends

Question 5

intersection

Answer 5

a set of points that figures have in common

Question 6

opposite rays

Answer 6

collinear rays with the same endpoint that form a line

Question 7

ray

Answer 7

part of the line that consists of one endpoint and all the points of the line on one side of the line

Question 8

segment

Answer 8

part of the line that consists of two points called endpoints and all of the points between them

Question 9

skew

Answer 9

lines that do not lie on the same plane

Question 10

postulate

Answer 10

Also known as an axiom is an accepted statement or fact

Question 11

theorem

Answer 11

A conjecture that is proven

Question 12

Conjecture

Answer 12

A conclusion reached by using inductive reasoning

Question 13

Undefined terms

Answer 13

There are 3 of them. Point, line, and plane. They are the building blocks for the rest of the subject.

Question 14

Point

Answer 14

In Euclidean geometry, a point is undefined. You can think of it as a location but it has no size.

Question 15

Line

Answer 15

In Euclidean geometry, a line is undefined. You can think of it as a straight path that extends in two opposite directions without end and has no thickness. Contains infinitely many points (which means A LOT).

Question 16

Plane

Answer 16

In Euclidean geometry, a plane is undefined. You can think of a plane as a flat surface that extends without end and has no thickness. It contains infinity many lines.

Question 17

complementary angles

Answer 17

two angles that add to 90 degrees

Question 18

supplementary angles

Answer 18

two angles that add to 180 degrees

Question 19

reason

Answer 19

The justification given in a two-column proof that we write on the right-hand side.

Question 20

statement

Answer 20

The claims we believe are true. We write these on the left-hand side of the two-column proof.

Question 21

two-column proof

Answer 21

A convincing argument that uses deductive reason. Statements are written on left-hand side and reasons are written on the right-hand side.

Question 22

addition property of equality

Answer 22

If a=b, then a + c = b + c

Adding the same thing to both sides of an equation without changing the solutions.

Question 23

subtraction property of equality

Answer 23

If a=b, than a - c = b - c

Subtracting the same thing to both sides of an equation without changing the solutions.

Question 24

Multiplication property of equality

Answer 24

if a=b, than ac = bc

Multiplying the same thing to both sides of the equation without changing the solutions.

Question 25

Division property of equality

Answer 25

If a=b and c isn’t 0, than a / c = b / c.

Dividing the same thing to both sides of the equation without changing the solutions. You can not divide by ZERO.

Question 26

Substitution property of equality

Answer 26

If a = b, then a can be substituted for b in any expression or equation.

Remember from the summer, this was SIDE to PART!

Question 27

Transitive property of equality

Answer 27

If a = b and b = c, than a = c.

Remember from the summer, this was SIDE to SIDE!

Question 28

congruent angles

Answer 28

angles that have the same measure

Question 29

angle bisector

Answer 29

a ray that divides an angle into two congruent angles

Question 30

compass

Answer 30

a geometric tool used to draw circles and parts of circles called arcs

Question 31

arc

Answer 31

a portion of the circumference of a circle

Question 32

straightedge

Answer 32

a ruler with no markings on it

Question 33

construction

Answer 33

a geometric figure made with only a straightedge and a compass

Question 34

perpendicular bisector

Answer 34

a line, segment, or ray that is perpendicular to the segment at its midpoint

Question 35

midpoint

Answer 35

the point that divides the segment into two congruent segments

Question 36

linear pair

Answer 36

a pair of adjacent angles whose noncommon sides are opposite rays

Question 37

angle addition postulate

Answer 37

if B is in the interior of