Geometry #1 Vocab

Question 1

Three undefined terms

Answer 1

Point, Line, and Plane. All of geometry is based on these three terms. You can’t prove they exist.

Question 2

Point

Answer 2

A location. Named with a capital letter.

Question 3

Line

Answer 3

A straight path of points that is indefinitely long. Named with any two points on the line.

Question 4

Plane

Answer 4

A flat surface of points that is infinitely large. Named with any three non - collinear points on the plane.

Question 5

Collinear points

Answer 5

Three or more points on the same line.

Question 6

Non - Collinear points

Answer 6

Three or more points not on the same line

Question 7

Ray

Answer 7

Part of a line with one endpoint. Name with endpoint and one “direction” point

Question 8

Endpoint

Answer 8

A point on the end of a segment or a ray

Question 9

Segment

Answer 9

Part of a line with two endpoints

Question 10

Parallel lines

Answer 10

Lines in the same plane that do not intersect

Question 11

Skew lines

Answer 11

Lines not in the same plane that do not intersect

Question 12

Parallel planes

Answer 12

Planes that do not intersect

Question 13

Congruent Segments

Answer 13

Line segments that have the same length

Question 14

Midpoint

Answer 14

A point that divides a segment into two congruent segments

Question 15

Angle

Answer 15

A figure formed from two rays that share the same endpoint

Question 16

Vertex

Answer 16

The common endpoint shared by the two rays of an angle

Question 17

Acute angle

Answer 17

Angle with a measure less than 90°

Question 18

Right angle

Answer 18

And angle with a measure equal to 90°

Question 19

Obtuse angle

Answer 19

An angle with a measure between 90° and 180°

Question 20

Straight angle

Answer 20

An angle with a measure of 180°

Question 21

Perpendicular lines

Answer 21

Lines that intersect to form right angles

Question 22

Complementary angles

Answer 22

Two angles with measures that add up to 90°

Question 23

Supplementary angles

Answer 23

Two angles with measures the add up to 180°

Question 24

Angle bisector

Answer 24

Ray that divides an angle into two congruent angles

Question 25

Adjacent angles

Answer 25

Angles that have a common vertex and side but do not overlap

Question 26

Vertical angles

Answer 26

The non-adjacent angles that are formed when two lines intersect. Vertical angles are always congruent.

Question 27

Transversal

Answer 27

A line that intersects with two or more other lines

Question 28

Triangle

Answer 28

A three sided polygon. Named a triangle using the three vertices. Order does not matter.

Question 29

Acute triangle

Answer 29

A triangle with all angles less than 90°

Question 30

Right triangle

Answer 30

A triangle with one right angle

Question 31

Obtuse triangle

Answer 31

A triangle with one obtuse angle

Question 32

Scalene triangle

Answer 32

A triangle with no congruent sides

Question 33

Isosceles triangle

Answer 33

A triangle with at least two congruent sides

Question 34

Equilateral triangle

Answer 34

Triangle with all sides congruent

Question 35

Polygon

Answer 35

A closed figure formed by joining segments

Question 36

Regular polygon

Answer 36

A polygon with all sides congruent and all angles congruent

Question 37

Diagonal

Answer 37

Hey segment connecting two nonconsecutive vertices in a polygon

Question 38

Quadrilaterals

Answer 38

Four sides, four angles. Sum of the angles is 360°

Question 39

Circle

Answer 39

All the points in a plane a given distance from a given point

Question 40

Radius

Answer 40

A segment with one endpoint at the center of a circle and one endpoint on the circle

Question 41

Chord

Answer 41

A segment with both end points on the circle

Question 42

Diameter

Answer 42

A chord that goes through the center of a circle

Question 43

Arc

Answer 43

Part of a circle

Question 44

Semicircle

Answer 44

Half of the circle. The ends of a diameter divides the circle into a semicircle.

Question 45

Circumference

Answer 45

The distance around a circle