We have to find the correct statement for angle A in a triangle ABC,
which is an obtuse triangle. We know that angle B is obtuse ( greater
than 90 degrees ). Therefore angles A and C must be less than 90
degrees. Angle A can not be congruent to angle B ( angle B > angle A
). It can be congruent to angle C but just in case that ABC is an
isosceles obtuse triangle. Answer: Angle A must be A ) less than 90
degrees.
