Honors Geometry - Chapter 1

Point

A location that has neither shape or size; named with a capital letter. (1.1)

Line

Made up of points with no thickness or width; named by lowercase script letter or by any two point on the line (1.1)

Plane

A flat surface made up of 3 points not on the same line; named by capital scripted letter or any three points on the plane (1.1)

Collinear Points

Points that lie on the same line (1.1)

Coplanar Points

Pints that lie on the same plane (1.1)

Intersection

1 or more points in common/ a set of points in common; symbol ∩ (1.1)

Definitions

an explanation using undefined terms or defined terms (1.1)

Space

boundless 3D set of all points contains lines and planes (1.1)

Line Segment

Can be measured because it has a start and end point (1.2)

Betweenness of Points

Point N is between points A & B only if A, B, and N are collinear; AN + NB = AB (1.2)

<———A———-N—————-B———>

Congruent Segments

Segments that have the same measure; symbol ≅ (1.2)

Distance on a Number Line

The distance between 2 points; lx₂ -x₁l (1.3)

Distance Formula (in a coordinate plane)

√(x₂-x₁)² + (y₂-y₁)²

(1.3)

Irrational Number

A number that can’t be expressed as a terminating or repeating decimal (1.3)

Midpoint

A point thats halfway bwtween a segment

Midpoint Formula (on a number line)

x₁+x_{2 / 2} 

(1.3)

Midpoint Formula (on a coordinate plane)

(x₁+x₂ / 2 , y₁+y₂ / 2)

(1.3)

Segment Bisector

Cut a segment into two equal pieces at the midpoint (1.3)

Rays

A ray has a starting point, but goes on forever (1.4)

Opposite Rays

Two rays with the same end point but go in opposite directions (1.4)

Angles

Formed by 2 rays with a common end point; <1 or <XYZ (1.4)

Angles in a Plane

divides a plane into 3 distinct parts; the interior, the angle, the exterior (1.4)

Degrees

1 degree = 1/360 of a turn around a circle (1.4)

Classifying Angles

Right <

Congruent Angles

Angle Bisector