Answer:
51° and 129°
Step-by-step explanation:
let x be the measure of one angle then x + 78 is the measure of the other
Supplementary angles sum to 180°, hence
x + x + 78 = 180, that is
2x + 78 = 180 ( subtract 78 from both sides )
2x = 102 ( divide both sides by 2 )
x = 51
Hence
the angles are 51° and 51 + 78 = 129°
