Le périmètre

In this video students can discover the concept of perimeter. They learn that the perimeter is the sum of the sides of a geometric figure. To facilitate the calculation of the perimeter of a square and a rectangle, there are two formulas: rectangle - P = (L+l) x 2 (be careful not to forget the parentheses because of the priorities of calculation, square - P = c x 4. The formulas must make sense to the students. It is not just a matter of learning the technique by heart but above all of understanding its meaning. Ideally, students should deduce the formulas from observations. When they see that there is a repetition, it makes sense to do x 2 or x 4.