1,根据韦达定理:ab=9M,a+b=3(M+1/2)设内切圆半径为r,则有(1/2)r(a+b+15/2)=1/2ab===>r(3(M+1/2)+15/2)=9M===>r=9M/(3M+9)=3M/(M+3)===>内切圆面积S=(1/2)πr^2=(1/2)*π*(3M/(M+3))^22,设半径为R,则有R^2=2^2+(R-1)^2===>R=2.5米3,设这个角为3X,则其对应外角为X,则有4X=180===>X=45===>这个角为3X=45*3=135度4,两圆外切有三条,外面两条,中间一条;两圆内切只有一条
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