In a triangle ABC the side BC is 3 cm shorter than the side AB, and the side AC is twice as long as BC.

Question

Find the lengths of the side of the triangle, if its perimeter is 15 cm. (Solve the problem by composing an equation)

 

Please HELP!!

Answer 1

BC = AB - 3 ---> BC + 3 = AB

AC = 2*BC 

 

AB + BC + AC = 15

 

BC + 3 + BC + 2 * BC = 15

 

4 * BC + 3 = 15

 

4 * BC = 12

 

BC = 12/4 = 3

 

AB = BC + 3 = 3 + 3 = 6

 

AC = 2 * BC = 2 * 3 = 6