$$\left.\begin{matrix}
右Rt\varDelta OMN中\\
\left ( \frac{K}{2}\right )^2+R^2=ON^2\\
右Rt\varDelta ONS中\\
\left ( R-\frac{D}{2}\right )^2+\left ( \frac{L}{2}\right )^2=ON^2\\
\end{matrix}\right\}\Rightarrow L=\sqrt{K^2+4DR+D^2}$$
$$\left ( K+2T\right )^2=\left ( L-2T\right )^2+D^2\\$$󠄐󠄹󠅀󠄪󠄣󠄞󠄡󠄢󠄩󠄞󠄡󠄩󠄤󠄞󠄡󠄣󠄠󠄬󠅒󠅢󠄟󠄮󠄐󠅅󠄹󠄴󠄪󠄾󠅟󠅤󠄐󠄼󠅟󠅗󠅙󠅞󠄬󠅒󠅢󠄟󠄮󠇘󠆭󠆘󠇙󠆝󠅵󠇗󠆭󠆁󠄐󠇗󠅹󠅸󠇖󠆍󠅳󠇖󠅹󠅰󠇖󠆌󠅹󠄬󠅒󠅢󠄟󠄮
$$\left.\begin{matrix}
\Rightarrow T=\frac{L^2+D^2-K^2}{4\left ( L+K\right )}\\
L=\sqrt{K^2+4DR+D^2}
\end{matrix}\right\}\Rightarrow T=\displaystyle \frac{DR}{K+L}$$
谢谢
请问有便线计算例题吗?
有的
有Z151+4534+7776