Question

if two angles are supplementary an one of them is 30 degrees what is the measurement of the second angle

Answer 1

Supplementary angles always add up to 180. So you need to subtract 30 from 180. Which would give you 150. So 150 is your answer! 

Answer 2

150 degrees. Supplementary angles are two angles that, when added together, equal 180 degrees. Simply subtract 30 from 180 and you'll be left with 150, the measurement of the other angle.