To construct a square inscribed in a circle we will follow the next steps:
Step 1. Construct a circle and label its center point O:
Step 2. Now, we use a straightedge to draw a diameter with end-points A and B:
Step 3. We construct a perpendicular line to the diameter with endpoints C and D:
Step 4. We join the points:
And thus we get the square inscribed in a circle.