By applying Pythagoras theorem in \(Δ\;PQR\),
\(\Rightarrow\) \((PQ)^2+ (PR)^2= (RQ)^2\)
\(\Rightarrow\) \((10)^2+ (24)^2= RQ^2\)
\(\Rightarrow\) \(100 + 576 = (QR)^2\)
\(\Rightarrow\) \(676 = (QR)^2\)
\(\Rightarrow\)\(QR= 26\) \(cm\)