Angles

* Two rays sharing a common endpoint. Angles are typically measured in degrees or radians.

* The space (usually measured in degrees) between two intersecting lines or surfaces at or close to the point where they meet.

Bisector

* A line segment, line, or plane that divides a geometric figure into two congruent halves.

* something means to cut it into two equal parts. The 'bisector' is the thing doing the cutting.

Chord

* A chord has both endpoints on the circle.

* A circle is a straight line segment whose endpoints both lie on the circle.

Diameter

* A line segment between two points on the circle or sphere which passes through the center. The word diameter is also also refers to the length of this line segment.

Equation

*A mathematical sentence built from expressions using one or more equal signs (=).

Formula

* An expression used to calculate a desired result, such as a formula to find volume or a formula to count combinations. Formulas can also be equations involving numbers and/or variables, such as Euler's formula.

Geometry

* The study of geometric figures in two dimensions (plane geometry) and three dimensions (solid geometry)

* the study of points, lines, triangles, quadrilaterals, other polygons, Etc...

Height of parallelogram

* The distance between opposite sides of a parallelogram. Formally, the shortest line segment between opposite sides. Altitude also refers to the length of this segment.

If and only If ( iff )

* A way of writing two conditionals at once: both a conditional and its converse.

* For example, the statement "A triangle is equilateral iff its angles all measure 60°" means both 

Joint Variation

* When we say z is jointly proportional to a set of variables, it means that z is directly proportional to each variable taken one at a time

Kite

* A quadrilateral may be convex or concave. A quadrilateral that is concave has an angle exceeding 180o

* All points between two given points (including the given points themselves).

Line Segment

Midpoint

* The point halfway between two given points.

* The formula for the midpoint between points (x₁, y₁) and (x₂, y₂)

Negative Number

* A real number less than zero. Zero itself is neither negative nor positive.

-5, -4, -3, -2, -1

Origin

* On the coordinate plane, the point (0, 0). That is, the point of intersection of the x- and y-axes. 

Parallelogram

* A quadrilateral with two pairs of parallel sides.