Question 874424
Suppose the angles have measures A,B,C with *[tex \large A \le B \le C] and *[tex \large A + B + C = 180^{\circ}].


We know that *[tex \large C < A+B] (given). Adding C to both sides, *[tex \large 2C < A+B+C \Rightarrow C < 90^{\circ}]. Since C is the largest of the three angles, the triangle is acute.