This document defines and classifies different types of quadrilaterals. It begins by defining a quadrilateral as a two-dimensional figure with four straight sides and four vertices, where the sum of the interior angles is always 360 degrees. It then classifies quadrilaterals based on the parallelism of their sides into parallelograms, trapezoids, and trapezoids. Parallelograms are further divided into squares, rectangles, rhombuses, and rhomboids based on their side lengths and angle measures. Trapezoids are separated into rectangle trapezoids, isosceles trapezoids, and scalene trapezoids depending on their parallel sides and

1. Quadrilateral

2. Definition
A two-dimensional figure with four
straight sides, and therefore with
four vertexes.
In all cases the sum of the angles is
360º.

3. According to the parallelism of their
sides quadrilateral can classify in:

4. Parallelograms
A four-sided figure with opposite sides equal
and parallel:
• Square
• Rectangle
• Rhombus
• Rhomboid

5. Square
A four-sided two-dimensional figure
with four sides equal in length and
all angles right angles.
Its diagonals are perpendicular and
equal and they cut each other in a
middle point.

6. Rectangle
A four-sided two-dimensional figure
with opposite sides equal and all
its angles right angles.
Its diagonals cut each other in a
middle point and they don’t form a
right angle but an oblique angle.

7. Rhombus
A four-sided two-dimensional figure
with four sides equal in length and
with opposite angles equal.
Its diagonals are perpendicular and
they cut each other in a middle
point.

8. Rhomboid
A four-sided two-dimensional figure
with opposite sides equal in length
and opposite angles equal.
Its diagonals cut each other in a
middle point and form an oblique
angle.

9. Trapezium
A four-sided two-dimensional figure
which two parrallel sides and they
classify in:
• Rectangle trapezoid
• Isosceles trapezoid
• Scalene trapezoid

10. Rectangle trapezoid
A four-sided two-dimensional figure
which two parrallel sides and two
equal angles.
Ist diagonals are unequal, oblique
and they don’t cut each other in a
middle point.

11. Isosceles trapezoid
A four-sided two-dimensional figure
which two parrallel sides and
opposite angles equal.
Ist diagonals are equal, oblique and
they don’t cut each other in a
middle point.

12. Scalene trapezoid
A four-sided two-dimensional figure
which two parrallel sides and four
unequal angles.
Ist diagonals are unequal, oblique
and they don’t cut each other in a
middle point.

13. Trapezoid
A four-sided two-dimensional figure
with four different angles.
Ist diagonals are unequal, oblique
and they don’t cut each other in a
middle point.