Final answer:
A clown who is 2 meters tall should look at a point 1 meter above the floor to see his feet in a full-length mirror, as the mirror's height is half the height of the person for them to view their entire body.
Step-by-step explanation:
To see his feet in a full-length mirror, a clown who is 2 meters tall needs to look at a specific point on the mirror. According to the Law of Reflection, the angle of incidence is equal to the angle of reflection, which implies that the light paths from his feet and the top of his head to his eyes form two right-angled triangles. To see his feet, the clown must look at the bottom of the mirror at a point that is half his height from the floor, i.e., 1 meter above the ground. This is because, for flat mirrors, any person can see their full body if the mirror's height is at least half their own height, irrespective of their distance from the mirror.
The height above the floor of the top and bottom of the smallest mirror in which a person can see both the top of their head and their feet is given by the problem as 1.715 m and 0.825 m, respectively, totaling 0.890 m for the height of the mirror, which is exactly half the person's height. By extension, this applies to the 2 m tall clown, so to see his feet in a full-length mirror, he must look at the point 1 meter from the floor.