click below
click below
Normal Size Small Size show me how
Unit 2 voc.
Question | Answer |
---|---|
`Three undefined terms in geometry | points, lines, and planes |
point | has no length, width, or thickness, but has a position. |
space | is the boundless 3-dimensional set of all points. |
line | has length, but no width or thickness. it extends without end in two directions. |
collinear points | points that lie on the same line are collinear points. |
plane | is a flat surface that has no thickness. it extends without end in all directions. |
coplanar | points and lines in the same plane |
intersecting lines | lines shaes a point |
intersecting planes | share an indefinite number of points who two planes intersect, the intersection is a line |
postulate | a statement accepted to be true without proof |
postulate 1-1 | through any two points there is exactly one line |
postulate 1-2 | if two lines intersect then they intersect in exactly one point. |
postulate 1-3 | if two planes then they intersect in axactly one line. |
postulate 1-4 | through any three noncollinear points there are exactly one plne. |
line segment | is a portion or a line between two points, called endpoints |
ray | is a part of a line that consists of an initial point and all points on the line that lie on the side of the initial point. |
opposite rays | start at the same point and go in opposite directions. |
parallel lines | are coplanar lines that do not intersect |
skew lines | are noncoplanar lines. therefore, they are ot parallel and not intersect. |
perpendicular lines | lines intersect to form right angles. |
parallel planes | are planes that do not intersect |
Ruler Postulate | the distance betwwen any two points on a number line is a absolute value of the difference of the corresponding numbers. |
congruent segments | twos egments with the same length. |
midpoint of a segment | a pont that divides a segment into two congruent segments. it bisects the segment.i |
bisector of a segment | any line, ray or other segment through a midpoint. |
angle | two arys that are connected at their endpoints |
protractor | device used to measure angles |
acute angle | less than 90% |
obtuse angle | greater than 90% |
right angle | exactly 90% |
congruent angles | with the same measures |
angle bisector | ray that divides an angle into 2 congruent(=)angle |
inductive reasoning | is a type reasoning that reaches conclusions based on a pattern of specific eaxamples or past events |
counterexample | is an example that proves a conjectures is false. |
conjecture | a conclusion reaches by using inductive reasoning. |