प्रश्न से,
PE = 6 cm, QE = 6.6 cm,
PF = 9 cm, RF = 9.9 cm
\(\therefore \frac{P E}{Q E}=\frac{6}{6.6}=\frac{1}{1.1}=\frac{10}{11}\)
\(\frac{P F}{R F}=\frac{9}{9.9}=\frac{1}{1.1}=\frac{10}{11}\)
\(\therefore \frac{P E}{Q E}=\frac{P F}{R F}\)
अतः थेल्स के विलोम से, EF || QR Proved.