[" 19.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.

Prove that ,the greatest rectangle inscribed in a given circle is a square.

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.