Question

平面按图所示由全等的正方形和全等的五边形铺成。被五边形覆盖的平面面积百分比最接近

The plane is tiled by congruent squares and congruent pentagons as indicated. The percent of the plane that is enclosed by the pentagons is closest to

$50$

$52$

$54$

$56$

$58$

答案：D

知识点：铺砖面积百分数

难度评级：1480

解答：

图案在一个由九个单位正方形组成的 $3 \times 3$ 方块中重复。其中九个小方格有四个未被五边形覆盖；剩余面积属于五边形。

所以五边形覆盖的比例为最接近 $56$ 。 $1 - \dfrac{4}{9} = \dfrac{5}{9} = 55.5\overline{5}\%,$

因此，正确答案是 D。

The pattern repeats over a $3 \times 3$ block of nine unit squares. Four of these nine squares are not covered by pentagons; the rest of the area belongs to the pentagons.

So the pentagons enclose $1 - \dfrac{4}{9} = \dfrac{5}{9} = 55.5\overline{5}\%,$ which is closest to $56.$

Thus, the correct answer is D.

2001 AMC 12 第 10 题

答案：D

难度评级：1480

解答：

其他年份的第 10 题