Draw a circle and any two of its (non-perpendicular) diameters. If you join the ends of these diameters, what is the figure obtained? What figure is obtained if the diameters are perpendicular to each other?

Steps:

1. Mark a point O as the centre of the circle and draw a circle of any suitable radius with O as centre.

2. Draw any two diameters AC and BD of the circle which are not perpendicular to each other.

3. Join the ends A, B, C and D in order.

The figure obtained on joining the ends of the two non-perpendicular diameters is a rectangle.

When the two diameters are perpendicular to each other, the figure obtained on joining the ends of the diameters is a square.

Hence, the figure obtained is a rectangle and a square when diameters are perpendicular to each other.