Question

Let A, B be the centres of two circles of equal radii; draw them so that each one of them passes through the centre of the other. Let them intersect at C and D. Examine whether AB and CD are at right angles.

Answer 1

Draw two circles of equal radii taking A and B as their centre such that one of them passes
through the centre of the other. They intersect at C and D. Join AB and CD. Yes, AB and CD intersect at right angle as < COB is 90 .