Let ABCD be the given rectangle.
AB = 12 cm, BC 35 cm
In ∆ABC, ∠B = 90° [Angle of a rectangle]
∴ AC2 = AB2 + BC2 [Pythagoras theorem]
= 122 + 352
= 144 + 1225
= 1369
∴ AC = \(\sqrt{1369}\) [Taking square root of both sides]
= 37 cm
∴ The diagonal of the rectangle is 37 cm.
