There are the following three punctuation marks on the school placard (the colored part in the picture). It is known that the radius of the great circle is r, the radius of the small circle is r, and

There are the following three punctuation marks on the school placard (the colored part in the picture). It is known that the radius of the great circle is r, the radius of the small circle is r, and R=2r. Now separate. The coloring area in the period is π [(2r) 2-R2] = 3π R2; The colored area in the comma is π (2r) 2× = 2π R2;

The colored area in the question mark is: 3π R2×+π R2 = 3π R2; Question marks use the most materials and commas the least.