3. angle a in triangle abc is obtuse. can angle b or angle c be obtuse? explain your reasoning

No. To be obtuse the angle has to be over 90 degrees. All triangles should add up to 180 degrees. If angle A is at the smallest degree it can be (90) then that leaves 90 degrees to be split between angle B and C. Therefore they would have to both be less than 90 degrees making them both acute angles.

Google it that might work