1953 AMC 12 第 29 题
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所有题目均经美国数学协会（MAA）官方合法授权使用。
29.
一个正方形的计算面积为 平方英寸，精确到万分之一平方英寸。该正方形边长的测量值有多少位有效数字？
The number of significant digits in the measurement of the side of a square whose computed area is square inches to the nearest ten-thousandth of a square inch is:
答案：D
小提示：
真实面积介于 平方英寸与 平方英寸之间
The true area lies from up to square inches
大提示：
对误差区间的两端开平方，观察边长有多少位数字保持不变
Take square roots of the error interval and see how many digits of the side are fixed
解答：
给出的面积表示真实面积满足 两边开平方，近似得到 因此，任何可能的边长精确到万分之一时都舍入为 。小数点后的末尾零是有效数字，所以 有五位有效数字。
因此，正确答案是 D。
The reported area means the true area lies in Taking square roots gives approximately Every possible side length therefore rounds to to the nearest ten-thousandth. The trailing zeros after the decimal are significant, so has five significant digits.
Thus, the correct answer is D.
其他年份的第 29 题
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- 1951 AMC 12
- 1952 AMC 12
- 1954 AMC 12
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- 1956 AMC 12
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