Question

一个边长为 $10$ 的等边三角形完全由不重叠的边长为 $1$ 的等边三角形填满。需要多少个小三角形？

An equilateral triangle of side length $10$ is completely filled in by non-overlapping equilateral triangles of side length $1.$ How many small triangles are required?

$10$

$25$

$100$

$250$

$1000$

答案：C

知识点：长度、面积与体积的缩放关系等边三角形

难度评级：880

解答：

大三角形边长是小三角形的 $10$ 倍，所以面积是小三角形的 $10^2=100$ 倍。

因为小三角形无重叠地铺满它，正好需要 $100$ 个。

所以正确答案是 C。

The large triangle has side length $10$ times that of a small triangle, so its area is $10^2=100$ times as large.

Since the small triangles tile it without overlap, exactly $100$ of them are required.

Thus, the correct answer is C.

2008 AMC 10B 第 7 题

答案：C

难度评级：880

解答：

其他年份的第 7 题