## Glossary of Math Definitions Chapter 1 Pearson Geometry

### Deck Info

#### Description

#### Tags

#### Recent Users

#### Other Decks By This User

- deductive reasoning
- takes known info to get to next step, each fact leads to next conclusion

- inductive reasoning
- base hypothesis on what is seen so far

- collinear points
- points that are on the same line

- coplanar points
- points that are on the same plane

- space
- set of all points

- postulates (axioms)
- accepted idea om geometry

- theory
- idea that has to be proven or justified

- Postulate (a)
- through any 2 points there is exactly one line (2 points determine a line)

- Postulate (b)
- If 2 lines intersect, they intersect at exactly one point

- Postulate (c)
- If 2 planes intersect, they intersect at exacly one line

- Postulate (d)
- Through any 3 noncollinear points there is exactly 1 plane

(three noncollinear points determine a plane)

- segment
- a part of a line consisting of 2 endpoints and all the points in between them

- ray
- a part of a line consisting of 1 endpoint and all the points of the line on 1 side of the endpoint

- opposite rays
- 2 collionear rays with the same endpoint

opposite rays always form a line

- parallel lines
- coplanar lines that do not intersect

- skew lines
- noncoplanar lines

- parallel planes
- planes that never meet

- Ruler Postulate:
- If you have a number line, all the points on that line have a 1 to 1 correspondence to the numbers on the line

- congruent
- 2 segments of the same length

If _AB is congruent to _CD then AB=CD and if AB=CD then _AB=_CD

- midpoint
- a midpt. of a segment is a point that divides a segment into 2 congruent segments (or two segments of equal length)

B is the midpt. of _AC if _AB=_BC and B is in between A and C (and visa versa)

- Segment Addition Postulate
- If A,B,C are collinear and B is between A and C then AB+BC=AC

- angle
- union of 2 rays w/ a common endpt.

the rays are the sides of the angle. The endpt. is the vertex of the angle

- Protractor Postulate
- If you look at all the possible angle measures between 0 and 180 and all the possible sized angles between a ray folded onto itself and a pair of opposite rays, there will be a 1 to 1 correspondence between the angle measures and the angles themselves

- Angle Addition Postulate
- If a point B is in the interior of <AOC then m<AOB + m<BOC = m<AOC

If <AOC is a straight angle then m<AOB+m<BOC =180

- Congruent Angles
- angles with the same measure

- constructions
- a way to create geometric objects using a straightedge and a compass

- perpendicular lines
- lines that intersect to form right angles

- perpendicular bisector of a segment
- a line, segment or ray that is perpendicular to a segment at its midpoint