问题
填空题
如果两圆相切,圆心距为7.5cm,一个圆的半径为4cm,则另一个圆的半径是______cm.
答案
当两圆外切时,
则圆心距等于两圆半径之和,此时另一个圆的半径是7.5-4=3.5(cm);
当两圆内切时,
圆心距等于两圆半径之差,则另一个圆的半径是7.5+4=11.5(cm).
故答案为:3.5cm或11.5.
如果两圆相切,圆心距为7.5cm,一个圆的半径为4cm,则另一个圆的半径是______cm.
当两圆外切时,
则圆心距等于两圆半径之和,此时另一个圆的半径是7.5-4=3.5(cm);
当两圆内切时,
圆心距等于两圆半径之差,则另一个圆的半径是7.5+4=11.5(cm).
故答案为:3.5cm或11.5.
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