Question | Answer |
Undefined Terms | A word that does not have a formal definition, but there is agreement about what the word means. 3 Undefined terms in Geometry: Point, Line, Plane |
Point | A point has no dimension. It is usually represented by a dot and labeled with a capital letter. One of the undefined terms in Geometry. |
Line | A line has one dimension. It is usally represented by a straight line with two arrowheads to indicate that the line extends without end in two directions. It is labeled by two points on the line with the line symbol written above. |
Plane | A plane has two dimensions. It is ually represented by a shape that look like a floor or a wall. It is labeled by a capital letter or 3 noncollinear points on the plane. |
Collinear Points | Points that lie on the same line. |
Coplanar Points | Points that lie on the same plane. |
Defined Terms | Terms that can be described using known words. |
Line Segment | Part of a line that consists of two points, called endpoints, and all points on the line that are between the endpoints. |
Endpoints | The points on either end of a line segment...or one end of a ray. |
Ray | Part of a line that consists of a point callend an endpoint and all points on the line that extend in one direction. |
Opposite Rays | Two rays that share a common endpoint and extend in opposite directions. |
Axiom | Another word for Postulate. |
Coordinate | The real number that corresponds to a point on a line. |
Distance | The absolute value of the difference of the coordinate of two points. *always positive. |
Between | When 3 points lie on a line, you can say that one point is between the other two. |
Congruent Segments | Line segments that have the same length. |
Midpoint | A point that divides, or bisects, a segment into two congurent segments. |
Segment Bisector | A point, ray, line, segment, or plane that intersects a segment at its midpoint. |
Angle | Consists of two different rays with the same endpoint. |
Acute Angle | An angle with measure between 0 and 90 degrees. |
Right Angle | An angle with a measure of 90 degrees. |
Obtuse Angle | An angle with measure between 90 and 180 degress. |
Straight Angle | An angle with measure of 180 degrees. |
Sides of an Angle | The rays that form the angle are called the sides. |
Vertex of an Angle | The common endpoint of the two rays that form an angle is called the vertex. |
Congruent Angles | Angles that have the same measure. |
Angle Bisector | A ray that divides an angle into two angles that are congruent. |
Complementary Angles | Two angles whose measures have the sum of 90 degrees. The sume of the measures of an angle and its complement is 90 degrees. |
Supplementary Angles | Two angles whose measures have the sum of 180 degrees. The sume of the measures of an angle and its suppplement is 180 degrees. |
Adjacent Angles | Two angles that share a common vertex & side, but have no common interior points. |
Linear Pair | Two adjadent angles whose noncommon sides are opposite rays. |
Vertical Angles | Two angles whose sides form two pair of opposite rays. *formed by intersecting lines. |
Polygon | A closed plane figure with three or more sides. |
Sides of a Polygon | Each line segment that forms a polygon. |
Vertex of a Polygon | Each endpoint of a side of a polygon. |
Convex | A polygon such that no line containing a side of the polygon contains a point in the interior of the polygon. |
Concave | A polygon that is not convex. (One or more lines that contain sides of the polygon also contains points in the interior of the polygon). |
n-gon | A polygon with n sides. |
Equilateral | All sides congruent. |
Equiangular | All interior angles congruent. |
Regular Polygon | A polygon that is both equilateral and equiangular. |
Perimeter | The distance around the outside of a polygon. |
Circumference | The distance around a circle. |
Area | The extent of a 2-dimensional surface enclosed within a boundary. |
Diameter | The distance across a circle through its center. |
Radius | The distance from the center of the circle to any point on the circle. |
Conjecture | An unproven statement that is based on observations. |
Inductive Reasoning | A process that includes looking for patterns and making conjectures. |
Counterexample | A specific case that shows a conjecture is false. |
Equation | A mathematical sentence using one or more equal signs. |
Solve an Equation | To find all values of the variables that make an equation true. |
Conditional Statement | A type of locial statement that has two parts, a hypothesis and a conclusion. |
Converse | The statement formed by exchanging (switching) the hypothesis and conclusion of a conditional statment. |
Inverse | The statement formed by negating the hypothesis and conclusion of a conditional statment. |
Contrapositive | The equivalent statement formed by negating the hypothesis and conclusion of the converse of a conditional statement. |
If-Then form | The format of a conditional statement. The "if" part is the hypothesis and the "then" part is the conclusion. |
Hypothesis | The "if" part of a conditional statement. |
Conclusion | The "then" part of a conditional statement. |
Negation | The opposite of a statment. The symbol is ~ |
Equivalent Statements | Two statements that are both true or both false. |
Perperdicular Lines | Two lines that intersect to form a right angle. |
Biconditional Statment | A statement that containe the phriase "if and only if". |