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Geo Ch 1 Definitions
Geometry Chapter 1 Definitions
Term | Definition |
---|---|
Acute angle | An angel with a degree measure less than 90 degrees. |
Adjacent angles | Two angles that lie in the same plane, have a common vertex and a common side, but no common interior points. |
Angle bisector | A ray that divides an angle into two congruent angles. |
Between | For any two points "A" and "B" on a line, there is another point "C" between "A" and "B" if and only if "A", "B", and "C" are collinear and AC + CB = AB |
Collinear | Points that lie on the same line |
Complementary angles | Two angles with measures that have a sum of 90 degrees. |
Coplanar | Points that lie in the same plane |
Line | A basic undefined term of geometry. A line is made up of points and has not thickness or width. In a figure, a line is shown with an arrowhead at each end. Lines are usually named by lowercase script letters. |
Linear pair | A pair of adjacent angles whose non-common sides are opposite rays. |
Midpoint | The point halfway between the endpoints of a segment. |
Obtuse angle | An angle with degree measure greater than 90 degrees and less than 180 degrees. |
Lines, segments, or rays are perpendicular iff | they intersect to form a right angle. |
Plane | A basic undefined term of geometry. A plane is a flat surface made up of points that has no depth and extend indefinitely in all directions. A plane is represented by a shaded, slanted 4-sided figure. |
Precision | The precision of a measurement depends on the smallest unit available on the measuring tool. |
Ray | A ray is a part of a line. It has one endpoint and extends indefinitely in one direction. Rays are named stating the endpoint first and then any other point on the ray. |
Regular Polygon | A convex polygon in which all of the sides are congruent and all the angles are congruent. |
Right angle | An angle with a degree measure of 90. |
Segment bisector | A segment, line, or plane that intersects a segment at its midpoint. |
Supplementary angles | Two angles with measures that have a sum of 180 degrees. |
Vertex | The common endpoint of two rays or more. |
Vertical angles | Two nonadjacent angles formed by two intersecting lines. |