Do triangles have at least 2 acute angles?

Answer 1

Yes.

The sum of the angles in a triangle is 180°

All angles in a triangle must be greater than 0° which means that the sum of any two angles must be less than 180°

If two angles are right angles (90°), their sum is 180° which is not less than 180°; thus at most one angle can be a right angle.

If one angle is a right angle and another is an obtuse angle (greater than 90°), then their sum is greater than 180°, which is not less than 180°; thus there can be at most one of a right angle and an obtuse angle.

If two angles are obtuse angles, their sum is greater than 180°, which is not less than 180°; thus there can be at most one obtuse angle.

If there is at most one right angle or an obtuse angle, there must be at least two acute angles.