9514 1404 393
Answer:
x = 12.5
Step-by-step explanation:
The value of x is part of the value of an angle in a triangle where the other angles are known. This suggests that the relevant theorem is the "angle sum theorem," which tells you <em>the sum of angles in a triangle is 180°</em>.
This gives you the equation ...
60° +60° +(4x+10°) = 180° . . . . total of all angles is 180°
4x +130° = 180° . . . . . . . . . . collect terms
4x = 50° . . . . . . . . . . . . subtract 130° from both sides
x = 12.5° . . . . . . . . . divide both sides by 4
