sommaire
I. Quadrilaterals
1. vocabulary of quadrilaterals
A quadrilateral is a polygon with four sides.
For this quadrilateral ABCD :
- two sides that have no vertex in common are said to be opposite.
- two sides that have a vertex in common are said to be consecutive.
Coding of a quadrilateral :
To name a quadrilateral, we note the vertices in the order in which we meet them when turning in a certain direction. Thus, the quadrilateral below can be written ABCD, ADCB, or BCDA.
2. particular quadrilaterals
A rectangle is a quadrilateral that has four right angles.
Example:
ABCD is a rectangle.
Its opposite sides are parallel and of the same length.
A rhombus is a quadrilateral that has four sides of equal length.
Example:
ABCD is a rhombus.
A square is a quadrilateral that has four right angles and four sides of equal length.
Example:
The quadrilateral ABCD is a square. Its four angles are right.
Its four sides have the same length: AB=BC=CD=DA.
A parallelogram is a quadrilateral that has its opposite sides parallel.
Example:
The quadrilateral ABCD is a parallelogram.
Its opposite sides are parallel: (AB)//(DC) and (AD)//(BC).
The square, rectangle and rhombus are particular parallelograms.
Did you get that lesson on quadrilaterals in 6th grade?
Un QCM sur les quadrilatères en 6ème.
Skills to learn about quadrilaterals:
- Know the definition of a quadrilateral;
- Know how to draw with geometry equipment (ruler, compass, square and protractor);
- Know the definitions and properties of the square, the rectangle, the trapezoid.
This course is in accordance with the officialnational education programs.
In addition, you can consult the exercises on quadrilaterals in the sixth grade.
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