Hey there!
Since these angles share the same vertex (point where the lines that make the angle meet), they are congruent (they have the same value). Therefore, we can write the following equation.
4x-12=2x+48
We add 12 to both sides.
4x=2x+60
We subtract 2x from both sides.
2x=60
We divide both sides by 2.
x=30
Now, we can plug this in to find the measure of angle ACB. Whenever you see an angle that is named with three letters, the middle one is its vertex and the other two are the end points.
m∠ACB=4(30)-12
m∠ACB=120-12
m∠ACB=108
I hope that this helps! Have a wonderful day!
