Chapter: Pythagoras Theorem· Mathematics Part 2 (Geometry)
Answer: \(10\sqrt{2}\) cm
Diagonal of a square \(= \sqrt{2} \times \text{side} = \sqrt{2} \times 10 = 10\sqrt{2}\) cm (about 14.14 cm).
(The diagonal is the hypotenuse of a right-angled isosceles triangle: \(d^2 = 10^2 + 10^2 = 200\), so \(d = 10\sqrt{2}\).) For side 5 cm the diagonal is \(5\sqrt{2}\) cm.