[tex]\it\left.\begin{aligned} MN||QS\Rightarrow\ \ \stackrel\frown{NQ}=\stackrel\frown{SM} \\ \\ MP||SR\Rightarrow\ \ \stackrel\frown{PR} =\stackrel\frown{SM} \end{aligned}\right\} \Rightarrow \stackrel\frown{NQ} =\stackrel\frown{PR} \Rightarrow \stackrel\frown{NP} +\stackrel\frown{PQ} =\stackrel\frown{PQ} +\stackrel\frown{QR} |_{-\stackrel\frown{PQ} }\ \ \Rightarrow\\ \\ \\ \Rightarrow \stackrel\frown{NP} =\stackrel\frown{QR} \Rightarrow NR||PQ[/tex]
