Solution: If the radius of the great circle is 2, then the half area of the great circle is 1/2× 2× 3. 14 = 6.28 square centimeters.

Because the ring width of the sector is half the width of the paper, that is, 1, which is smaller than the radius of 2- 1= 1.

So the half area of the small circle:1/2×/kloc-0 /×1× 3.14 =1.57 square centimeters.

So the sector area: 6.28-1.57 = 4.71cm2.