| Geometry Vocab 1 | Definitions |
| counterexample | an example of a conditional statement in which the hypothesis is fulfilled and the conclusion is not fulfilled proving the statement to be false |
| parallel vectors | vectors that have the same or opposite direction |
| base | the noncongruent side in an isosceles triangle |
| ray | consists of an initial point and all the points on a line to one side of that point; a half line |
| Law of Syllogism | p implies q, q implies r, therefore p implies r |
| scalene triangle | a triangle with no congruent sides |
| interior angles of a triangle | the angles inside the triangle |
| complementary angles | two angles whose sum equals 90 degrees |
| exterior angles of a triangle | the angles adjacent to the interior angles |
| equilateral triangle | a triangle with three congruent sides |
| skew lines | lines that do not lie in the same plane |
| linear pair | two adjacent angles whose noncommon sides form opposite rays |
| congruent segments | segments that have the same length |
| alternate interior angles | two angles that lie between two lines intersected by a transversal and on opposite sides of the transversal |
| perpendicular lines | two lines that intersect to form a right angle |
| angle bisector | a ray that divides the angle into two congruent angles |
| transversal | a line that intersects two or more coplanar lines at different points |
| corresponding angles | angles that occupy corresponding positions when a transversal intersects two lines |
| midpoint of a segment | the point that divides the segment into two congruent segments |
| contrapositive of p implies q | not q implies not p; true if and only if p implies q is true |
| angle | consists of two different rays that have the same initial point |
| obtuse angle | an angle with a measure greater than 90 degrees and less than 180 degrees |
| equiangular triangle | a triangle with three congruent angles |
| segment bisector | a segment, ray, line, or plane that intersects a segment at its midpoint |
| hypotenuse | the side opposite the right angle in a right triangle |
| vector | a quantity that has both quantity and magnitude |
| parallel lines | coplanar lines that do not intersect |
| legs | the sides of a right triangel that form the right angle; the two congruent sides in an isosceles triangle |
| Law of Detatchment | p implies q, p is true, therefore q is true |
| consecutive interior angles | two angles that lie between two lines intersected by a transversal on the same side of the transversal |
| straight angle | an angle that measures 180 degrees |
| line segment | consists of two endpoints and all the points that lie on a line between those two endpoints |
| opposite rays | two rays that share the same initial point and form a straight line |
| oblique lines | intersecting lines that are not perpendicular |
| intersecting lines | coplanar lines that have exactly one point in common |
| vertical angles | angles whose sides form two pairs of opposite rays |
| right angle | an angle with a measure of 90 degrees |
| converse of a conditional statement | formed by interchanging the hypothesis and the conclusion |
| coincident lines | the same line |
| adjacent angles | two angles that share a common vertex and side, but have no common interior points |
| congruent angles | angles that have the same measure |
| acute triangle | a triangle with three acute angles |
| acute angle | an angle with a measure greater than 0 degrees and less than 90 degrees |
| rignt triangle | a triangle with one right angle |
| obtuse triangle | a triangle with exactly on obtuse angle |
| isosceles triangle | a triangle with at least two congruent sides |
| biconditional statement | p if and only if q; equivalent to writing p implies q and q implies p |
| congruent triangles | triangles whose corresponding angles and sides are congruent |
| conditional statement | a statement made up of two parts, the hypothesis (if p) and the conclusion (then q) |
| collinear points | points that are on the same line |
| supplementary angles | two angles whose sum equals 180 degrees |
