Answer:
x=42°
Step-by-step explanation:
In any triangle, when all three angles are added together, their sum will always be 180°:
∠1+∠2+∠3=180
Insert any known values:
[tex]29+109+x=180[/tex]
Simplify the addition:
[tex]138+x=180[/tex]
Use inverse operations to find angle three. Subtract 138 from both sides:
[tex]138-138+x=180-138\\\\x=42[/tex]
Therefore, the unknown angle is 42°.
:Done
