AMC 8 1990 Problem 15

AMC8 1990 年第 15 题

四边形与多边形★★★☆☆

The area of this figure is

100\text{ cm}^2

. Its perimeter is [figure consists of four identical squares]

此图形的面积为

100\text{ cm}^2

。其周长是

[图形由四个相同的正方形组成]

正确答案 · Correct Answer

解析 · Solution

Solution 1

Since the area of the whole figure is

100\text{ cm}^2

, each square has an area of

\displaystyle \frac{100}{4} = 25\text{ cm}^2

and a side length of

\sqrt{25} = 5\text{ cm}

The boundary of this figure is made of 10 segments, each of length

5\text{ cm}

, so it perimeter is

10 \cdot 5=50\text{ cm}

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