教圆弧的画法,如题：上弧20196.7,下弧12267.22,上下弧间距8000,求两圆的半径.

上弧C1=20196.7,下弧C2=12267.22,上下弧间距L=8000,求两圆的半径R1,R2?
弧所对的圆心角为A.
R1-R2=L=8000
A=C1/R1=C2/R2
R2=R1*(C2/C1)=R1*(12267.22/20196.7)
R1-R2=R1-R1*(12267.22/20196.7)=8000
20196.7*R1-12267.22*R1=8000*20196.7=161573600
7929.48*R1=161573600
R1=161573600/7929.48=20376.317
R2=R1-8000=20376.317-8000=12376.317
A=C1/R1=20196.7/20376.317=0.991185弧度=0.991185*180/PI=56.79度