Question

这个 $12$ 乘 $18$ 的大矩形区域中，有几分之几被涂色？

What fraction of the large $12$ by $18$ rectangular region is shaded?

$\dfrac{1}{108}$

$\dfrac{1}{18}$

$\dfrac{1}{12}$

$\dfrac{2}{9}$

$\dfrac{1}{3}$

知识点：面积分数

整个区域面积是 $12 \times 18 = 216$ 。涂色区域宽 $3$ 、高 $6$ ，面积为 $3 \times 6 = 18$ 。

所以涂色比例是 $\dfrac{18}{216} = \dfrac{1}{12}$ 。等价地，它是整个区域的 $\dfrac14$ 的 $\dfrac13$ 。

所以正确答案是 C。

The whole region has area $12 \times 18 = 216.$ The shaded region is $3$ wide and $6$ tall, with area $3 \times 6 = 18.$

So the shaded fraction is $\dfrac{18}{216} = \dfrac{1}{12}.$ Equivalently, it is $\dfrac13$ of $\dfrac14$ of the whole.

Thus, the correct answer is C .