1st Semester Geometry Final - Vocabulary Flashcards
Acute Angle
An angle with measure between 0 and 90 degrees.
Adjacent Angles
Two angles that share a common vertex and side, but have no common interior points.
Altitude of a Triangle
The perpendicular segment from one vertex of the triangle to the opposite side or to the line that contains the opposite side.
Angle Bisector
A ray that divides an angle into two angles that are congruent.
Centroid
The point of concurrency of the thee medians of the triangle.
Circumcenter
The point of concurrency of the three perpendicular bisectors of the triangle.
Complementary Angles
two angles whose measures have the sum 90 degrees. the sum of the measures of n angle and its complement is 90 degrees.
Collinear Points
Points that lie on the same line.
Equiangular
Angles are congruent.
Equidistant
The same distance from one figure as from another figure.
Equilateral
Sides are congruent.
Hypotenuse
In a right triangle, the side opposite the right angle.
Incenter
The point of concurrency of the three angle bisectors of the triangle.
Isosceles Triangle
A triangle with at least two congruent sides.
Linear Pair
Two adjacent angles whose non common sides are opposite rays.
Median
A segment from one vertex of the trangle to the midpoint of the opposite side.
Midpoint
A point that divides, or bisects, a segment into two congruent segments.
Midsegment of a Triangle
A segment that connects the midpoints of two sides of the triangle.
Obtuse Angle
An angle with measure between 90 and 180 degrees.
Orthocenter
The point at which the lines containing the three altitudes of the triangle intersect.
Perpendicular Lines
Two lines that intersect to form a right angle.
Polygon
A closed plane figure with the following properties. 1) It is formed by three or more line segments called sides. 2) Each side intersects exactly two sides, one at each endpoint, so that no two sides with a common endpoint are collinear.
Postulate
A rule that is accepted without proof. Also called “Axiom.”
Quadrilatoral
A polygon with four sides.
Scalene Triangle.
A triangle with no congruent sides.
Segment Bisector
A point, ray, line, segment, or plane that intersects a segment at its midpoint.
Skew Lines
Lines that do not intersect and are not coplanar.
Supplementary Angles
Two angles whose measures have the sum 180 degrees.
Theorem
A true statement that follows as a result of other true statements.
Vertical Angles
Two angles whose sides form two pairs of opposite rays.
