Show that of all the rectangles inscribed in a given fixed circle, the square has the maximum area.

Show that of all rectangles inscribed in a given fixed circle, the square has the maximum area.

Show that of all the rectangles inscribed in a given circle, the square has the maximum area.

Show that of all the rectangles inscribed in a given circle,the square has the maximum area.

Show that of all rectangles inscribed in a given circle, the square has the maximum area.

Show that of all rectangles inscribed in a given circle the square has maximum area.

Show that of all isosceles triangles inscribed in a given circle, the equilateral triangle has the greatest area.

Prove that among all the rectangles of the given perimeter, the square has the maximum area.

Show that, of all the rectangles with a given area, the square has the smallest perimeter.