any three measures can make up some triangle?
read up on the "converse of the pythagorus theorem"
for a triangle with sides a, b, c where c is the longest side
if c^2 < (a^2 + b^2) then the triangle is "acute"
if c^2 = (a^2 + b^2) then the triangle is "right" angled
if c^2 > (a^2 + b^2) then the triangle is "obtuse"
test (c^2 - (a^2 + b^2)) in math2.0calc
