According to the conditions, judge whether the angle ABC is an acute triangle, a right triangle or an obtuse triangle. (1) angle a = 76 degrees, angle B = 89 degrees. (2) angle a-angle B = angle C (3) Angle a = 20 degrees, angle B = 3, angle c

According to the conditions, judge whether the angle ABC is an acute triangle, a right triangle or an obtuse triangle. (1) angle a = 76 degrees, angle B = 89 degrees. (2) angle a-angle B = angle C (3) Angle a = 20 degrees, angle B = 3, angle c

According to the conditions, the angle ABC is an acute triangle, a right triangle or an obtuse triangle
(1) Angle a = 76 degrees, angle B = 89 degrees, acute triangle
(2) Angle a-angle B = angle c right triangle
(3) Angle a = 20 degrees, angle B = 3, angle c obtuse triangle