Question

if a triangle has an obtuse angle, then the other two angles are acute

Answer 1

yes that is definitely true, do you know why?

Answer 2

I am trying to prove this statement with out using angle measure. The most I can establish is that I need to use the Exterior Angle Theorem

Answer 3

an obtuse angle is an angle between 90-180 and lets say we have one that is 95 deg
then the other two triangles must be acute angles(less than 90deg) to add up to 180 deg.
Note: all three angles in a triangle have to add up to 180 deg