Draw a circle and any two of its 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? How do you check your answer?

The required figure may be drawn as follows:

Step: 1 Draw a circle with centre O with a suitable radius.
Step II: AB and CD are any two diameters.
Step III: On joining the end points of the diameters, we get a quadrilateral ACBD.
Step IV: We note that OA = OB = OC = OD [Same radius]
and AC = DB, AD = BC
∠A = ∠C = ∠B = ∠D = 90°
Thus ACBD is a rectangle.

Once again, if the diameters are perpendicular to each other, we obtain
AC = DB = AD = BC
Thus, ACBD is a square.