Chapter 1

Undefined Terms

Words that’s do not have formal definitions but there is and agreement about what they mean

Point, line, plane

Point

Location in space that is represented by a dot and has no dimension

Line

One dimensional. Represented by a line with two arrowheads but extends without end

Plane

A flat surface made up of points that has two dimensions and extends without end and is represented by a slanted 4 sided figure

Collinear points

Points that lie on the same line

Coplanar points

Points that lie on the same plane

Defined terms

Terms that can be described using known words

Segment, ray, opposite ray

Line segment or segment

Consists of two endpoints and all the points between them

Endpoints

Points that represent the end os a line segment or ray

Ray

Consists of one endpoint and all the points that lay on the same side

Opposite rays

Two rays that share an endpoint but go in opposite directions

Intersection

Set of points two or more geometric figures have in common

Postulate or Axiom

Rule that is accepted without proof

Coordinate

Real number that corresponds to a point on a line

Distance

Absolute value of the difference of two coordinates on a line

Construction

Geometric drawing that uses a limited set of tool( compass and straightedge)

Congruent Segments

Line segments that have the same length

Between

When 3 points are collinear one point of between the other two

Midpoint

The points the divided the segment into two congruent segments

Segment Bisector

A point, ray, line, line segment, or plane that intersects the segment at its midpoint

Angle

Set of points consisting of two different rays that have the same endpoint

Vertex

The common endpoint of two rays in an angle

Sides of an Angle

Ray of an angle

Interior of an angle

The region that contains all the points between the sides of an angle

Exterior of an angle

The region that contains all the points outside of an angle

Measure of an angle

The absolute value of the difference between the real numbers matched with the two rays that form the angle on a protractor

Acute angle

An angle with a measure greater than 0 degrees but less than 90 degrees

Right Angle

Angle that has a measure of 90 degrees

Obtuse angle

An angle that has a measure greater than 90 degrees but less that 180 degrees

Straight Angle

An angle with a measure of 180 degrees

Congruent angles

Two angles with the same measure

Angle Bisector

A ray that divides the angle into two congruent angles

Supplementary angles

Two angles whose measures have a sum of 180 degrees

Complementary Angles

Two angles whose measures have a sum of 90 degrees

Adjacent Angles

Two angles that share a common vertex and side but have no common interior points

Linear Pair

Two adjacent angles whose no common sides are opposite rays

Ruler Postulate

using a ruler to find the measure or subtraction when they share the same x or y value

Segment addition Postulate

If B is between A and C then AB+BC=AC

Protractor Postulate

Subtract initial protractor value from Final to get angle measure

Angle addition Postulate

If P is in the interior of angle RST the angleRSP+anglePST=angleRST

Midpoint formula

(( x1+x2)/2, (y1+y2)/2)

Distance Formula

Radical (x2-x1)²+ (y2-y1)²