We are given lengths: base a, height h and side b and vertex point B

  1. Draw top of parallelogram:
    •    Draw segment from B of length a so that |\overline{AB}| .
  2. Draw height of parallelogram:
    •    Draw line through B perpendicular (normal) to \overline{AB} .
    •    Draw circle with center B and radius h.
    •    Find intersection point of this circle and the perpendicular. Rename point H.
  3. Draw base line (parallel to |\overline{AB}| )
    •    Draw line through H perpendicular to the perpendicular.
  4. Draw third vertex (find side)
    •    Draw circle e with center B and radius b.
    •    Find intersection point C of this circle and base line.
  5. Draw fourth vertex
    •    Draw circle f with center C and radius a.
    •    Find intersection point D of this circle and base line.
  6. Draw parallelogram
    •    Draw segments \overline{BC} , \overline{CD} and \overline{DA} .

Check construction:

     Click and drag free points A and B. ABCD should remain a parallelogram.
     Click and drag sliders. ABCD should change in size, but remain a parallelogram.

Save construction.


  • Draw line segment from B to H.
  • Change color and thickness/line styles of all lines in construction to make more readable.
  • Write dynamic formulas for perimeter and area: Input LL=2*a+2*b (enter) and Input AA=a*h (enter).
  • Write dynamic text for formulas:
        "Perimeter = "+LL (enter) and "Area = "+AA (enter).

Related themes:


Page last modified on August 27, 2008, at 12:49 PM