How many right-angled triangles can be formed with a diameter of the
circle as base and with third vertex on the circumference of the circle? How many of them
are right isosceles triangles?
Infinite (as the diameter subtends a 90° angle with any point on the
circumference and there is no limit to the number of points on the circumference) as
shown.
No. of right isosceles triangles = 2 (Triangles ABC and ABD as shown).