Quadrilaterals: A Guide
Triangle
Rules
Has 4 sides
Must have exactly four sides
Has 4 corners
Must have exactly four vertices
Has 1+ pair parallel sides
At least one pair of opposite sides are parallel
Has 2 pairs parallel sides
Both pairs of opposite sides are parallel
Has all right angles
All four corners are 90 degrees
Has all equal sides
All four sides are the same length
Shape Names
Quadrilateral
Any 4-sided polygon
Trapezoid
Quadrilateral with 1+ pair parallel sides
Parallelogram
Quadrilateral with 2 pairs parallel sides
Rectangle
Parallelogram with all right angles
Rhombus
Parallelogram with all equal sides
Square
Rectangle with all equal sides (or Rhombus with right angles)