sort by best latest
dingdong says
If the two angles add to 180°, we say they "Supplement" each other.
So, the answer is: 180  78 = 102

Comment
cristina327 says
The supplement of an angle of 78 is 102. Supplementary angles are angles whose sum is equal to 180. To get the measurement of a supplement of an angle subtract that angle from 180. Subtracting 78 from 180 will give you 102.

Comment