algebra
posted by Chris .
A triangle has sides of lengths 20, 28, and 32. A similiar triangle has a side of length 15 and another of length 24. How long is the third side of this triangle?

for similar triangles, the ratio of the sides of the first triangle is equal to the ration of the corresponding sides of the second triangle,, like:
let h1 = height of 1st triangle
let h2 = height of 2nd triangle
let b1 = base of 1st triangle
let b2 = base of 2nd triangle
therefore, if they are similar triangles,
(h1)/(b1) = (h2)/(b2)
thus in the question, we can write:
let x = third side
20/15 = 32/24 = 28/x
simplifying:
4/3 = 28/x
solving for the third side,
x = 21
hope this helps~ :) 
20/15 = 4/3
28/24 = nope
32/24 = 4/3 yes
so
20 > 15
32 > 24
28(3/4) = 21
so
20 , 28 , 32
>
15 , 21 , 24