SOLUTION: The lengths of the three sides of a triangle are in the ratio 4:5:7. The longest is 21 cm longer than the shortest side. What is the length of the shortest side?

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Question 981580: The lengths of the three sides of a triangle are in the ratio 4:5:7. The longest is 21 cm longer than the shortest side. What is the length of the shortest side?
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
4x:5x:21x are ratios, too.

We know that 21x-21cm=4x, because the longest side is 21 cm longer.
17x=21cm, by collecting terms and separating variable from constant.
x=(21/17); 4x=(84/17)cm SHORTEST SIDE, ANSWER.
Check: The sides would be (84/17), (105/17), and (441/17)
They can be made into mixed numbers, but these are acceptable.
Longest side is (441/17)-(84/17) (shortest side)=(357/17)
(357/17)=21, all units cm.