设半径为 r
则r^2=(7.8/2)^2+(r-1.1)^2
r^2 =3.9^2 +r^2-2.2r +1.21
2.2r =3.9^2+1.21 =15.21+1.21=16.42
r=8.21/1.1 =82.1/11
已知圆的弦长7.8米,1米,求圆的半径
设半径为 r
则r^2=(7.8/2)^2+(r-1.1)^2
r^2 =3.9^2 +r^2-2.2r +1.21
2.2r =3.9^2+1.21 =15.21+1.21=16.42
r=8.21/1.1 =82.1/11