A PARALLELOGRAM-SHAPED ENVELOPE
Maths Workshop: Maths in an envelope
 
1. A PARALLELOGRAM-SHAPED ENVELOPE

Now let's try and imagine an envelope which, instead of being rectangular, is shaped like a parallelogram.

This kind of envelope is not very practical and probably would not be accepted by courier companies. However, we could use them to send things to our friends for a bit a fun.

In the following window there is an envelope like the one we've described, but it is closed. 

 

Move the control points at the top of the envelope to change its size.

Vertex H moves horizontally and vertex L moves freely so that the envelope is in the shape of a parallelogram.

Point O inside the parallelogram is also a control that allows its position to be changed in any direction.

1.- Try to draw the original piece of paper needed to make the envelope yourself before you unfold it on the screen. 

2.- What do we call the shape we get when the envelope is unfolded?

3.- Why isn't this shape a quadrilateral?

4.- Make an envelope like the one below and explain the steps you need to go through to make it.

       
           
  Author: Ángel Cabezudo Bueno (2001)
Adaptation to DescartesJS: Ángel Cabezudo Bueno
 
Proyecto Descartes. Año 2022
 
 

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