设两直角边为a,b,半径为r
1,ab=24
2,a*a+b*b=4r*r
3,a+b+2r=12√2
把3式移项成a+b=12√2-2r
再同时平方:a*a+b*b+2ab=288+4r*r-48√2r
把1,2式分别代入就能求出r