Answer :
Let the 3 sides be a,b and c. Take the longest side c:-
then for an acute triangle c^2 < a^2 + b^2
and for an obtuse triangle c^2 > a^2 + b^2
then for an acute triangle c^2 < a^2 + b^2
and for an obtuse triangle c^2 > a^2 + b^2