Respuesta :
It is 12 because there are 180 degrees in a set of supplementary angles and 12 times 10 equals 120, plus 60 equals 180.
Answer:
Option C, 12°
Step-by-step explanation:
When a pair of angles are supplementary that means their sum will be equal to 180°.
By this definition 10x + 60° = 180°
10x = 180 - 60
10x = 120°
x = 12°
Option C, 12° is the answer.