Geometric object

Equilateral

In geometry, an equilateral triangle is a triangle in which all three sides are equal. In the familiar Euclidean geometry, equilateral triangles are also equiangular; that is, all three internal angles are also congruent to each other and are each 60°.

Parallel lines

Lines are parallel if they are always the same distance apart (called "equidistant"), and will never meet.

Angle

In planar geometry, an angle is the figure formed by two rays, called the sides of the angle, sharing a common endpoint, called the vertex of the angle. Angles formed by two rays lie in a plane, but this plane does not have to be a Euclidean plane

Isosceles

An isosceles triangle is a triangle with (at least) two equal sides. In the figure above, the two equal sides have length and the remaining side has length . This property is equivalent to two angles of the triangle being equal. An isosceles triangle therefore has both two equal sides and two equal angles.

Angle Measurement

A straight angle is the same as half the circle and is 180° whereas a right angle is a quarter of a circle and is 90°. You measure the size of an angle with a protractor. Or could be shown by an arc on the figure to indicate which angles that are congruent.

Equiangular

An equiangular triangle is a triangle where all three interior angles are equal in measure. Because the interior angles of any triangle always add up to 180°, each angle is always a third of that, or 60° ... See Equilateral Triangles.

Base Angles

There is a special triangle called an isosceles triangle. In an isosceles triangle, the base angles have the same degree measure and are, as a result, equal (congruent). Similarly, if two angles of a triangle have equal measure, then the sides opposite those angles are the same length.

Leg

A leg of a triangle is one of its sides. For a right triangle, the term "leg" generally refers to a side other than the one opposite the right angle (which is termed the hypotenuse). Legs are also known as catheti.

Postulate/Axiom

Postulate. A statement, also known as an axiom, which is taken to be true without proof. Postulates are the basic structure from which lemmas and theorems are derived. The whole of Euclidean geometry, for example, is based on five postulates known as Euclid's postulates.

Base

Image result for base mathwww.mathopenref.com In mathematics, a base or radix is the number of different digits or combination of digits and letters that a system of counting uses to represent numbers. For example, the most common base used today is the decimal system. Because "dec" means 10, it uses the 10 digits from 0 to 9.

Line segment

In geometry, a line segment is a part of a line that is bounded by two distinct end points, and contains every point on the line between its endpoints. A closed line segment includes both endpoints, while an open line segment excludes both endpoints; a half-open line segment includes exactly one of the endpoints.

Right

In the figure above, set the angle to 90° and see that instead of a small arc, the angle is marked with a small square symbol. If you see this, the angle measure in degrees is usually omitted. Note also that right triangles are those where one interior angle is a right angle.

Cartesian Coordinate Plane

A Cartesian coordinate system is a coordinate system that specifies each point uniquely in a plane by a pair of numerical coordinates, which are the signed distances to the point from two fixed perpendicular directed lines, measured in the same unit of length.

Scalene

A scalene triangle is a triangle that has three unequal sides, such as those illustrated above. SEE ALSO: Acute Triangle, Equilateral Triangle, Isosceles Triangle, Obtuse Triangle, Triangle. CITE THIS AS: Weisstein, Eric W. "

Congruent

Exactly equal in size and shape. Congruent sides or segments have the exact same length. Congruent angles have the exact same measure. For any set of congruent geometric figures, corresponding sides, angles, faces, etc. are congruent.

Obtuse

Obtuse angle. From Latin: obtusus - "blunt" Definition: An angle whose measure is greater than 90° and less than 180°

Acute

Refers to an angle less than 90°, or to a shape involving angles less than 90°. It is the opposite of obtuse, which refers to an angle greater than 90°.

Regular

Regular Polygon. more ... A polygon is regular when all angles are equal and all sides are equal (otherwise it is "irregular"). This is a regular pentagon (a 5-sided polygon).

Vertex

The common endpoint of two or more rays or line segments. Vertex typically means a corner or a point where lines meet. For example a square has four corners, each is called a vertex. The plural form of vertex is vertices.

Collinear

Three or more points , , , ..., are said to be collinear if they lie on a single straight line . A line on which points lie, especially if it is related to a geometric figure such as a triangle, is sometimes called an axis. Two points are trivially collinear since two points determine a line.

Complementary

Two Angles are Complementary when they add up to 90 degrees (a Right Angle). They don't have to be next to each other, just so long as the total is 90 degrees. Examples: 60° and 30° are complementary angles. 5° and 85° are complementary angles.

Supplementary

Two Angles are Supplementary when they add up to 180 degrees. They don't have to be next to each other, just so long as the total is 180 degrees. Examples: 60° and 120° are supplementary angles. 93° and 87° are supplementary angles.

Adjacent

Two angles are Adjacent when they have a common side and a common vertex (corner point) and don't overlap. Angle ABC is adjacent to angle CBD. Because: they have a common side (line CB) they have a common vertex (point B)