An angle that is the supplement of an acute angle must be what?

If one angle is the supplement of another, we know that their sum is 180 degrees.
So let one angle be A and the supplement be B. We know the measure of A+B=180.
If A is acute that means its measure is less than 90 degrees. The supplement must therefore have measure more than 90 degrees. We could say the supplement of an acute angle must be an obtuse angle. Remember obtuse angle is one that less than 180 degrees and more than 90.