Chapter: Pythagoras Theorem· Mathematics Part 2 (Geometry)
Answer: QR = 16
In \(\Delta PQR\), seg PM is a median, so M is the midpoint of QR.
By Apollonius theorem, \(PQ^2 + PR^2 = 2PM^2 + 2QM^2\).
\(290 = 2 \times 9^2 + 2QM^2 = 162 + 2QM^2\) \(\therefore 2QM^2 = 128\) \(\therefore QM^2 = 64\) \(\therefore QM = 8\).
\(QR = 2 \times QM = 2 \times 8 = 16\).