Answer to Question #158513 in Algebra for ?

Question

the length of the of a triangle are in ratios 4:5:9 the perimeter of the triangle 72 cm what are the length of the side

Answer 1

Solution.

Let k be the coefficient of proportionality, then one side is 4k cm, the second side is 5k cm,

and the third side is 9k cm. The perimeter of the triangle is 72 cm, from here we get the equation

$$4k+5k+9k=72.$$

Solve the equation

$$18k=72,$$ $$k=72/18,$$ $$k=4.$$

Then, one side is 4 ∙ 4 = 16 cm, the second side is 4 ∙ 5 = 20 cm, and the third side is 

4 ∙ 9 = 36 cm.

Answer. $16cm, 20cm, 36cm.$