Prove that there is no triangle whose altitudes are of length 4, 7, and 10 units.
Let
a,b,c represent the lengths of the triangle sides in non-increasing order and
S its area.
2*S=4a=7b=10c
a should be less than b+c .
S/4 should be less than S/7+S/10.
But 1/4=.25 17/70=.2467
So - no such triangle