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Geometry Honors
Geometry Honors Module 1 Vocab
Term | Definition |
---|---|
Point | A specific location that is represented by a dot. Points are named with a capital print letter. |
Line | A connected straight path. Lines are named with a lower case cursive letter, or two points on the line. |
Plane | A flat surface. A plane is named with a capital cursive letter, or three non-collinear letters. |
Line segment | A portion of a line that consists of two points -endpoints- and all of the points between them. |
Ray | A portion of a line that starts at an endpoint, and continues forever in one direction. |
Collinear | Points that lie on the same line. |
Non-collinear | Points that are not on the same line. |
Coplanar | Points that lie on the same plane. |
Non-coplanar | Points that do not lie on the same plane. |
Parallel lines | Parallel lines are lines that are in the same place, but they do not intercept. |
Postulate | A statement that is accepted as true without proof. |
Segment Postulate Addition | If B is between A and C, then AB + BC= AC. |
Distance formula | The square root of (x2-x1) squared +(y2-y1) squared |
Midpoint | The point that divides the line segment into two segments that have the same length. |
Segment bisector | A line, ray, or other figure that passes through the midpoint of a segment. |
Midpoint formula | m(x1+x2/2, y1+y2/2) |
Angle | A figure formed by two rays with the same endpoint. An angle is usually named with three letters, the middle letter being the vertex. An angle can also be named by its vertex, and if applicable, its number. |
Degrees | A common measurement unit for circular arcs. Angles are measured by degrees. |
Protractor | A device used to measure degrees in angles. |
Vertex | The common endpoint of an angle. |
Sides | The rays of an angle. |
Acute angle | An angle that measures between 0 and 90 degrees. |
Right angle | An angle that measures exactly 90 degrees. |
Obtuse angle | An angle that measures between 90 degrees and 180 degrees. |
Straight angle | An angle that measures exactly 180 degrees. |
Angle bisector | An angle bisector is a ray that divides an angle into two angles that both have the same measurement. |
Angle Addition Postulate | If S is the interior of angle PQR, then the measurement of PQS + the angle of SQR= the measurement of PQR. |
Transformation | A function that changes the position, shape, and/or size of a figure. |
Preimage | A figure that is used as the input of a transformation. |
Image | A figure that is used as the output of a transformation. |
Translation | Slide |
Reflection | Flip |
Rotation | Turn |
Coordinate notation | A way to write a rule for a transformation on a coordinate plane. The notation uses an arrow to show how the transformation changes the coordinate of general point. |
Rigid motion (isometry) | A transformation that changes the position of a figure without changing the size or shape of the figure. Translations, reflections, and rotations are rigid motions. |
Properties of a rigid motion | A rigid motion preserves distance, angle measure, betweenness, collinearity, and parallelism. |
Dilation | An image in which the preimage coordinates have been multiplied or divided by the same factor. |
Vertical stretch | An image in which the preimage y has been multiplied by a number greater than one, but x stayed the same. |
Vertical compression | An image in which the preimage y has been multiplied by a number less than one but greater than zero. |
Horizontal stretch | An image in which x is multiplied by a number greater than one, but y stayed the same. |
Conjecture | A statement that is believed to be true based on a pattern or observation. |
Inductive reasoning | The process of reasoning that a rule or statement may be true by looking at specific cases. |
Deductive reasoning | The process of using logic to prove whether all cases are ture. |
Theorem | A statement that you can prove is true by using a series of logical steps. |
Counterexample | An example that shows a conjecture to be false. |
Conditional statement | A statement that can be written in the form "If p, then q" where p is the hypothesis and q is conclusion. |
Linear pair | A pair of adjacent angles whose non-common sides are opposite rays. |
Supplementary angles | Two angles who measure add up to 180 degrees. |
The Linear Pair Theorem | If two angles form a linear pair, then they are supplementary. |