No i dint think it is 2×8-4=12 and 8 is not equal to 12 :)
Both angles WILL have the same measure.
So,
3x-10= x+40 (you have to set the equations equal to one another)
Now, add 10 to both sides.
3x=x+50
Subtract x on both sides.
2x=50
Divide both sides by 2.
x=25
Now, plug in x.
(25 +40)= 65
(3(25)-10)= 65
x equals 25 and both angles are equal to 65. Or "B".
I hope this helps!
~cupcake
Arc FE: 76°
arc DEF: 180°
arc CFD: 284°
arc DFE: 256°
102 degrees, that is if the circles radius equals 1.
