Geometry Vocabulary Chapter 1

Inductive Reasoning

A type of reasoning that reaches conclusions based on a pattern of specific examples or past events.

Hypothesis

Conclusion reached after using Inductive Reasoning. Also a conjecture.

Conjecture

Conclusion reached after using Inductive Reasoning. Also a hypothesis.

Counterexample

An example for which a conjecture/hypothesis is false.

Isometric Drawings

Allows us to show 3 sides of a figure from a corner view. Shown in 3-D.

Orthographic Drawings

Allows us to show 3 dimensions of a figure, but from three specific 2-D viewpoints. These are Top, Front, and Right.

Foundation Drawings

Shows the base of a structure and gives numbers to show the height of the structure. Looks like the "Top" version of the Orthographic.

Net

2-D pattern that can be folded to create a 3-D figure.

Point

Location in space represented by capital letters.

Line

Series of points that extend into opposite directions without end.

Collinear Points

Points that fall upon the same line.

Plane

Flat surface in space with no thickness, may contain lines points, rays, etc. Named by 3 non collinear points.

Segment

Portion of a line containing two endpoints and all points between.

Ray

Portion of a line containing one endpoint and all points on 1 side of that endpoint.

Opposite Rays

2 collinear rays with the same endpoint.

Parallel Lines

Coplanar Lines that do not intersect.

Skew Lines

Non coplanar, Non parallel, not on the same plane lines.

Parallel Planes

Planes that do not intersect.

Midpoint

A point that divides a segment into 2 congruent segments.

Angle

Two rays with a shared or similar endpoint. This endpoint is called a vertex.

Obtuse Angles

90<x<180

Acute Angles

0<x<90

Right Angles

x=90

Bisector

A line, segment, ray, or plane that intersects a segment at its midpoint.

Angle Bisector

A ray that divides an angle into two congruent angles.

Perpendicular Lines

Lines that intersect and form right angles.

Perpendicular Bisector

The Perpendicular Bisector of a segment or ray that is perpendicular to the segment at the midpoint.

Distance Formula

d = ?[( x? - x?)� + (y? - y?)�]

Midpoint Formula

(x?+x?)/2, (y?+y?)/2

Perimeter

Total distance around the outside of an object.

Area

The space occupied inside of a 2-D figure.