There are eight equidistant points on a circle. How many right-angled triangles can be drawn using these points as vertices and taking the diameter as one side of the triangle?

Given a circle with eight equidistant points - A, B, C, D, E, F, G, and H - we can form four unique diameters by connecting opposite points. Each diameter, with its opposite vertex on the circle, forms a right-angled triangle. Therefore, using the remaining six points, we can create six unique right-angled triangles for each diameter. Hence, the total number of right-angled triangles that can be formed is 4 (diameters) × 6 (unique triangles per diameter) = 24.