The sum of the squares of the deviation of all points from the best line is the least it can be.

各点与最佳线偏离的平方之和，是所能获得的最小值。

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For example the square on hypotenuse of a right Angle triangle is equal to the sum of the squares of the other two sides.

例如，直角三角形斜边的平方，等于其它两边的平方和。

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An example is: the assembly tolerance is equal to the square root of the sum of the squares of the individual tolerances.

例如，装配公差等于单个公差的平方和的平方根。

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