Triangle ABC is an obtuse triangle with the obtuse angle at vertex B angle A must b A.less than 90 B.greater than 90 C.congruent to angle B C.congruent to angle C
The three angles of a triangle always have to add up to 180degrees. If one of the angles is obtuse(which means it is bigger than 90degrees), the other two angles will both always be less than 90 degrees.