[tex]c)\frac{SP}{PD}=\frac{1}{1}\ \textless \ =\ \textgreater \ \frac{SP}{SD}=\frac{1}{2}\\
Verificam\ teorema\ lui\ Thales\ :\\
\frac{SP}{SD}=\frac{SR}{SB}\ \textless \ =\ \textgreater \ \frac{1}{2}=\frac{2}{3}(F)=\ \textgreater \ PR\ este\ intersectat\ cu\ planul\ (ABC)[/tex]