The sides of a triangle are in the ratio 3 : 4 : 5. if the perimeter of the triangle is 84 cm, find its sides. PLEASE ANSWER FAST!!!! Share with your friends Share 0 Sanjari Kalantri answered this Dear Student, We are given: Perimieter of triangle = 84 cm, sides of triangle are in the ratio 3:4:5.Let the sides of the triangle be 3x, 4x and 5x.∴ 3x + 4x + 5x = 84⇒ 12x = 84⇒ x = 7Thus, the three sides of the triangle are 3x = 21 cm, 4x = 28 cm, and 5x = 35 cm. -2 View Full Answer