Investigate parallelograms

Explore this interactive page. The sliders allow you to change the shape of the parallelogram. Watch the measurements as you change its shape.

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Some facts are always true about every parallelogram.

As you change the shape of the parallelogram what is always true about:

  • the opposite sides?

  • the opposite angles?

  • the diagonals?

Do you notice any other facts that are always true about every parallelogram?

A parallelogram divided into two triangles

Open GeoGebra and follow these steps (DOCX 809kB) to create a new applet.

Explore your applet:

  • How does the applet help you to see that the opposite sides are equal?

  • What does the applet demonstrate about the opposite angles?

  • What can you add to your applet so that it demonstrates that the diagonals have been bisected?

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