Question | Answer |
parallel | lines that do not intersect have the same slope |
perpendicular lines | lines that intersect to form right angles |
alternate interior angles | two non-adjacent angles that lie on the opposite sides of a transversal between two lines that the transversal intersects (a description of the location of the angles); |
arc | part of a circle contained between two points located on the circle |
arc length | the length in linear measure of an arc of a circle; the product of the ratio of the arc measure and 360º and the circumference of the circle |
bisector (of a line segment) | a line, segment, ray, or plane that intersects a segment at its midpoint |
bisector (of an angle) | a line or ray that divides the angle into two congruent angles |
central angle | an angle whose vertex is the center of the circle and whose sides are radii of the circle. |
chord | a line segment whose endpoints lie on the circle |
circle | all points lying in one plane that are equidistant from a fixed point (the center) |
conditional statement | A statement that can be written in the form “If p, then q.” p is the hypothesis and q is the conclusion. Symbolically, if p, then q can be written as p-->q. |
contrapositive | the hypothesis and conclusion are both reversed and negated. “If p, then q.” becomes “If not q, then not p.” |
converse | the hypothesis and conclusion are reversed. “If p, then q.” becomes “If q, then p.” |
convex polygon | a polygon in which no diagonal contains points outside of the polygon. |
corresponding angles (parallel lines) | two angles that lie on the same side of a transversal, in corresponding positions with respect to the two lines that the transversal intersects. |
corresponding angles (in polygons) | angles that are in the same position in different plane figures |
cosine | a trigonometric function abbreviated cos In a right triangle, the ratio of the length of the leg adjacent to the reference angle to the length of the hypotenuse |
exterior angle of a polygon | an angle formed when one side of a polygon is extended; the angle is adjacent to an interior angle of the polygon |
Law of Syllogism | From (p implies q) and (q implies r) we conclude (p implies r). |
Law of Detachment | p and (p implies q) we conclude q. |
linear pair | two adjacent angles whose non-common sides are opposite rays; the sum of these angles is 180 |
major arc | an arc that measures 180º or more |
midpoint | the point halfway between the endpoints of a segment divides a segment into two congruent segments |
minor arc | an arc that measures less than 180º |
orthogonal drawings | the two dimensional top view, front view, and right-side view of a three-dimensional drawing |
platonic solids | the five regular polyhedra: tetrahedron, hexahedron, octahedron, dodecahedron, or icosahedron |
proof | a valid argument in which all of the premises are true |
regular polygon | a polygon that has congruent sides and congruent angles |
same-side interior angles (consecutive angles) | two angles that lie on the same side of a transversal and between the lines cut by the transversal, in corresponding positions with respect to the two lines that the transversal intersects. |
scale | the ratio of any length in a scale drawing to the corresponding actual length; the lengths may be in different units |
secant | a line, ray, or segment that intersects a circle at two points (i.e. that contains a chord) |
sine | a trigonometric function abbreviated sin. In a right triangle, the ratio of the length of the leg opposite the reference angle to the length of the hypotenuse. |
skew lines | non-coplanar lines that do not intersect |
tangent (to a circle) | a line that intersects a circle in exactly one point |
tangent (trigonometric function) | a trigonometric function abbreviated tan; In a right triangle, the ratio of the length of the leg opposite the reference angle to the length of the leg adjacent to the given angle. |
transversal | a line that intersects two or more other lines in the same plane at different points |