If two angles are supplement of each other, then one of the angles must be acute

this is true

Step-by-step explanation:

a supplementary angle adds up to 180 degrees. two accute angles would equal to around 90 and two obtuse angles would add up to more than 180. two right angles are perpendicular and they could work but since the question asks about acute and obtuse, its true that one angle must be acute and the other must be obtuse for it to add up to 180.