On a large placard, the three punctuation marks shown in the picture below should be drawn: period, comma, and question mark. Known half of a great circle

Solution: Period: S=3.14×(2r)2-3.14r2=9.42r2;

Comma: S＝

1

2

×3.14×(2r)2＝6.28r2;

Question mark: S＝

3

4

×[3.14×(2r)2?3.14r2] 3.14r2=10.205r2;

Because 10.205r2>9.42r2>6.28r2,

So the question mark paint is used more.