Geometry quadrilaterals 8

Diagonal

Joining 2 non-consecutive vertices in a convex polygon.

Interior Angle

Angles inside the polygon.

Exterior Angle

Angles formed by extending a side of the figure outside the polygon.

Parallelogram

A quadrilateral with both pairs of opposite sides parallel.

Rhombus

An equilateral parallelogram.

Rectangle

An equiangular parallelogram.

Square

A quadrilateral that is both equilateral and equiangular.

Biconditional

A statement that is true both ways, expressed as 'if and only if'.

Convex Polygon

A polygon where all angles point outwards.

Regular Polygon

A polygon where all sides are equal.

Triangle

A polygon with 3 sides.

Quadrilateral

A polygon with 4 sides.

Pentagon

A polygon with 5 sides.

Hexagon

A polygon with 6 sides.

Heptagon

A polygon with 7 sides.

Octagon

A polygon with 8 sides.

Nonagon

A polygon with 9 sides.

Decagon

A polygon with 10 sides.

Hendecagon

A polygon with 11 sides.

Dodecagon

A polygon with 12 sides.

Interior Angle Sum

Calculated as (n-2)180, where n is the number of sides in the polygon.

Exterior Angle Sum

Always equals 360 degrees for a polygon.

Supplementary Angles

Interior and exterior angles of a polygon are supplementary.

Sum of Interior Angles Theorem

The sum of interior angles of a polygon is (n-2)180.

Quadrilateral Interior Angles Corollary

The sum of interior angles of a quadrilateral is always 360 degrees.

Polygon Exterior Angles Theorem

The sum of the measures of exterior angles of a convex polygon is 360 degrees.

Properties of Parallelograms

Opposite sides are congruent, opposite angles are congruent, consecutive interior angles are supplementary, and diagonals bisect each other.

Rectangle Corollary

A quadrilateral is a rectangle if and only if it has four right angles.

Square Corollary

A quadrilateral is a square if and only if it is both a rhombus and a rectangle.

Convex polygon

All angles point outwards

Regular polygons

All sides equal