AN UNUSUAL RECTANGULAR ENVELOPE
Maths Workshop: Maths in an envelope
 
1. AN UNUSUAL RECTANGULAR ENVELOPE
In the following window there is a rectangular envelope. However, in this envelope the point where the vertices meet is not necessarily found in the centre of the rectangle.

In this window move the control points around the outside of the envelope to change its size and the position of the point where the four vertices meet.

Without unfolding the envelope: Can you visualise the shape of the piece of paper needed to make this envelope?

  1. Move the 4 control points until you get an envelope which is 5 units wide and 4 units high, making sure the point where the vertices meet is not in the centre.

  2. Make a rectangular, paper envelope which measures 12 x 6 cm where the vertices meet at a point which is 2cm from the bottom side and 2 cm from the left-hand side of the envelope. Describe how you did it.

  3. Can you make an envelope from any quadrilateral?

  4. What do the quadrilaterals used to make envelopes all have in common?

  5. Can we make a rectangular envelope by folding any sheet of paper or rectangular piece of paper?

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

Creative Commons License
Except where otherwise noted, this work is licensed under a de Creative Commons License