Those are vertical angles
The answer is C and here are the steps
<span>Using the information we have
3x+4=40
Do the same to each side of the equation to eliminate for x.
3x+4=40 Minus 4 from each side
3x=40-4
3x=36
Divide 3 from each side
x=36/3
x=12
AC=3x+4
insert the value of x
3(12)+4=40
AC=40
AD=20</span>
15.00-5.00-2.00-2.00= $6.00