Given that <1 and <2 are supplementary angles and that m<1=115 degrees , explain how to find the measure of the complement of <2

Answer 1

<2 = 180-115 = 65
co(<2) = 90-65 = 25

or, make a general rule for the complement of any angle's supplement:
90-(180-x) = x-90
115-90=25