Question 949734
Simply use the given numbers for the side lengths and follow what the theorem says.


{{{system(x+2x>10,2x+10>x,x+10>2x)}}}


That is how to start.  Simplify each inequality for x, and accept only the POSITIVE inequality solution.  You are looking for an intersection.


{{{system(3x>10,2x>-10,10>x)}}}


{{{system(x>10/3,x>-5,x<10)}}}


Obviously you cannot use anything between {{{-5}}} and {{{0}}}.  That second inequality is not very helpful now.  The statements which work are combined as {{{highlight(10/3<x<10)}}}.