Question

Triangle PQR is right angle at Q. |PQ| = 3a cm and |QR| =4a cm. Determine |PR| in terms of a

Answer 1

A^2 + B^2=C^2 Pythagorean’s Theorem

(3a)^2 + (4a)^2 = C^2

9a^2 + 16a^2 = C^2

a^2(9+16) = C^2

a^2(25) = C^2

sqrt ((a^2(25)) = sqrt (C^2)

5a=C=|PR|

shortcut would have been to recognize a 3-4-5 triangle