A triangle must have at least two (2) acute angles.
-- An acute angle is an angle less than 90°.
-- If the triangle only had one of them, then both of
the other angles would each be bigger than 90°.
-- If they were, then just those 2 alone would add up to more than 180°.
-- That can't happen, because the 3 angles in a triangle
always add up to exactly 180°.
-- So the triangle can't have only 1 acute angle.
It must have either 2 of them, or else 3 of them.