Flashcards: Geometry vocabulary Test
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Created by:
Sabster411 on September 20, 2010
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Terms | Definitions |
|---|---|
 collinear | Points that lie on the same line |
| coplanar | Points that lie in the same plane |
| endpoint | a point at one end of a segment or the starting point of a ray. |
| line | a straight path that has no thickness and extends forever. |
| opposite rays | two rays that have a common endpoint and form a line. |
| plane | a flat surface that has no thickness and extends forever. |
| point | a location and has no size. It is represented by a dot. |
| postulate | or axiom, is a statement that is accepted as true without proof. |
| ray | a part of a line that starts at an endpoint and extends forever in one direction. |
| segment | the part of a line consisting of two points and all points between them. |
| undefined terms | cannot be defined by using other figures. |
| coordinate | A point corresponds to one and only one number on the ruler |
| distance | the absolute value of the difference of the coordinates |
| length | distance between A and B ̶̶ |
| congruent segments | segments that have the same length |
| construction | a way of creating a figure that is more precise |
| midpoint | the point that bisects the segment into two congruent segments. the center point |
| bisect | divides |
| segment bisector | any ray, segment, or line that intersects a segment at its midpoint. It divides a segment into two equal parts at its midpoint. |
| angle | a figure formed by two rays, or sides, with a common endpoint |
| vertex | common endpoint |
| interior of an angle | The set of all points between the sides of the angle |
| exterior of an angle | the set of all points outside the angle. |
| measure | usually given in degrees. |
| degree | 1 out of 360 of a circle |
| acute angle | an angle less then 90 degrees |
| right angle | a 90 degree angle |
| obtuse angle | an angle more then 90 degrees |
| straight angle | a 180 degree angle |
| congruent angles | angles that have the same measures |
| angle bisector | the line segment, line, or ray that bisects an angle |
| adjacent angles | two angles in the same plane with a common vertex and a common side, but no common interior points. |
| linear pair | a pair of adjacent angles whose noncommon sides are opposite rays |
| complementary angles | angles that add up to 90 degrees |
| supplementary angles | angles that add up to 180 degrees |
| vertical angles | two nonadjacent angles formed by two intersecting lines. opposite angles |
| coordinate plane | a plane that is divided into four regions by a horizontal line (x-axis) and a vertical line (y-axis) |
| leg | two sides that form a right angle |
| hypotenuse | the side that stretches from one leg to the other |
| inductive reasoning | process of reasoning that a rule or statement is true because specific cases are true |
| conjecture | A statement you believe to be true based on inductive reasoning |
| counterexample | To show that a conjecture is false, you have to find only one example in which the conjecture is not true. This case is called a..... |
| conditional statement | a statement that can be written in the form "if p, then q." |
| hypothesis | the part p of a conditional statement following the word if. |
| conclusion | the part q of a conditional statement following the word then. |
| truth value | either true (T) or false (F). It is false only when the hypothesis is true and the conclusion is false. |
| negation | p is "not p," written as ∼p |
| converse | he statement formed by exchanging the hypothesis and conclusion. |
| inverse | the statement formed by negating the hypothesis and the conclusion. |
| contrapositive | the statement formed by both exchanging and negating the hypothesis and conclusion. |
| logically equivalent statements | Related conditional statements that have the same truth value |
| Deductive reasoning | building a logical argument/explanation by making conjecture based on established facts |
| Law of syllogism | If p -> q and q-> r are true conditionals, then p -> r are also true.. |
| Law of detachment | if P -> q is a true conditional and p is true, then q is true |
| angle additon | two angle add into one whole angle.. |