Prove that there is no triangle whose altitudes are of length 4, 7, and 10 units.
The area found by base*height/2 should be the same for each of 3 sides, so given sides a, b, c
2a=7b/2=5c
Side by the triangle inequality b+c > a
solving for b in terms of a gives b = 4a/7
solving for c in terms of a gives c = 2a/5
b + c = 4a/7 + 2a/5 = 34a/35
Which is not greater than a so the triangle cannot exist.

Posted by Jer
on 20131004 09:07:31 