Thread: Word problem - quadratics

The hypotenuse of a right angle triangle is 15 cm. the sum of the legs of the triangle is 21 cm. Find the legs of the triangle.

How do I solve this?

ps I have to solve this using the quadratic formula

I would figure that by scaling, you can make making the hypotenuse 5, then knowing this, and the 3-4-5 rule, you could make the legs, 3 and 4 respectively, then to convert back to the parameters of the problem, you'd multiply back by 3, giving you and which if added, give you the 21 cm stated in the problem.

Originally Posted by dancingqueen9

The hypotenuse of a right angle triangle is 15 cm. the sum of the legs of the triangle is 21 cm. Find the legs of the triangle.

How do I solve this?

Let and denote the legs of the right triangle, we know that



and



Now solve that system of equations

You should get (its in white so you don't have to see it, if you wish to just highlight below)
x=9 and y=12 or y=9 and x=12...they are describing the same triangle

Alright, thanx guys!