| A | B |
|---|
| Acute Angle | an angle with measure less than 90 degrees |
| acute triangle | a triangle with three acute angles |
| Adjacent Angles | coplanar angles which share a vertex and a ray |
| alternate exterior angle converse | if alternate exterior angles are congruent then the lines are parallel |
| alternate exterior angle theorem | if lines are parallel, then alternate exterior angles are congruent |
| alternate exterior angles | a pair of angles on alternate sides of a transversal on the outside of the parallel lines |
| alternate interior angles | a pair of angles on alternate sides of a transversal on the inside of the parallel lines |
| altitude | a segment perpendicular to one side of a polygon to the opposite vertex |
| Angle Addition postulate | the sum of the measures of adjacent angles is the measure of the angle constructed by their union |
| Angle bisector | a ray which divides an angle into two congruent angles |
| ASA Theorem | If an corresponding angle, side and angle of two triangles are congruent, then the triangles are congruent. |
| Bisect | to divide into two congruent parts |
| centroid | the center of gravity |
| circumcenter | the intersection of all perpendicular bisectors of a triangle |
| Circumference | the distance around a circle |
| circumscribed circle | the circle which intersects a triangle exactly at its vertices |
| Collinear | on the same line |
| Complementary Angles | two angles whose measures have a sum of 90 degrees |
| Concave Polygon | a polygon which contains interior points which are endpoints of a segment which is not entirely in the polygon |
| Conclusion | the part of a conditional statement after the "then" |
| conditional statement | a statement which can be written in "if-then" form |
| conjecture | a statement which is believed to be true based on a pattern observed through examples |
| consecutive interior angles | angles on the same side of the transversal inside the parallel lines |
| contrapositive | a conditional statement formed by switching and negating the hypothesis and conclusion of another conditional statement |
| converse | a conditional statement formed by switching the hypothesis and conclusion of another conditional statement |
| Convex Polygon | a polygon in which all segments whose enpoints on the interior of the polygon also are in the interior of the polygon |
| Coplanar | on the same plane |
| corresponding angles | angles on the same side of the transversal on the same side of parallel lines |
| corresponding angles converse | if corresponding angles are congruent, then the lines are parallel |
| corresponding angles theorem | if lines are parallel then the corresponding angles are congruent |
| counterexample | an example proving a conjecture to be false |
| CPCTC Theorem | corresponding angles of congruent triangles are congruent |
| Decagon | a ten sided polygon |
| deductive reasoning | an argument using logic to draw conclusions |
| Dodecagon | a twelve sided polygon |
| equidistant | the same distance between from two objects |
| equilateral triangle | a triangle with three congruent sides |
| Exterior Angle Theorem | the measure of an exterior angle of a triangle is equal to the sum of the measures of the remote interior angles |
| Heptagon | a seven sided polygon |
| Hexagon | a six sided polygon |
| Hypotenuse | the side of a right triangle opposite the right angle |
| hypothesis | the part of a conditional statement after the "if" and before the "then" |
| incenter | the intersection of all angle bisectors of a triangle |
| inductive reasoning | an argument using examples and patterns to draw conclusions |
| inscribed circle | the circle which intersects each side of a traingle exactly once |
| isosceles triangle | a triangle with two congruent sides |
| Linear Pair | adjacent supplementary angles |
| median | a segment from the midpoint of one side of a triangle to the opposite vertex |
| Midpoint | the point halfway between the endpoints of a segment |
| midsegment | the segment of a triangle whose endpoints are midpoints of two distinct edges of the triangle |
| Midsegment Theorem | a midsegment of a triangle is parallel to the base and half the length of the base. |
| Obtuse angle | an angle whose measure is greater than 90 degrees |
| obtuse triangle | a triangle with one obtuse angle |
| Octagon | an eight sided polygon |
| orthocenter | the intersection of all altitudes of a triangle |
| parallel lines | coplanar lines which do not intersect |
| Pentagon | a five sided polygon |
| perpendicular bisector | the segment perpendicular to another segment through its midpoint. |
| perpendicular lines | two lines which intersect at 90 degrees |
| point slope form | the equation of a line in the form y - yo = m(x - xo) |
| Polygon | a planar object constructed by line segments intersecting exactly at endpoints |
| Polygon Exterior Angle Sum Theorem | the sum of exterior angles of a convex polygon is 360 degrees |
| Polygon Interior Angle Sum Formula | the sum of interior angles of a convex n-gon is (n-2)180. |
| preimage | the object before a tranformation |
| Pythagorean Theorem | the square of the hypotenuse is the sum of the squares of the legs of a right triangle |
| Quadrilateral | a four sided polygon |
| reflection | a transformation in which the segment adjoining each point in the preimage and it's corresponding image is perpendicular to a fixed line |
| Reflexive Property of Congruence | all objects are congruent to themselves |
| remote interior angle | an interior angle which is not adjacent to an exterior angle |
| right angle | an angle whose measure is 90 degrees |
| right triangle | a triangle with one right angle |
| rotation | a transformation in which the preimage and it's preimage are equidistant to a point |
| SAA Theorem | if corresponding side, angle, angle are congruent then triangles are congruent |
| SAS Theorem | if corresponding side, angle, side are congruent then triangles are congruent |
| scalene triangle | a triangle with sides of three different measures |
| segment bisector | a line which cuts a segment in half |
| skew lines | noncoplanar nonintersecting lines |
| slope | the ratio of difference in y-coor over difference in x-coor |
| slope intercept form | the equation of a line in the form y = mx + b |
| SSS Theorem | if corresponding side, side, side are congruent then triangles are congruent |
| supplementary angles | angles whose measures add to up to 180 degrees |
| Symmetric Property of Congruence | the property that if object A is congruent to object B then object B is congruent to object A |
| Transformation | a change in position, size or shape of a figure or graph |
| Transitive Property of Congruence | of object A is congruent to object B and object B is congruent to object C then object A is congruent to object C |
| translation | a shifting of an object |
| transversal | a line that intersects two coplanar lines at two distinct points |
| Triangle Inequality Theorem | the sum of the measures of two sides of a triangle is less than the third side |
| Triangle Sum Theorem | the sum of the measures of the interior angles of a triangle is 180. |
| vertex | the intersection of two edges of an angle |
| Vertical Angle Theorem | the angles opposite intersecting lines are congruent |
