Answer
$x=40$
$\angle(1)=130^{\circ}$
Work Step by Step
Since $\angle(1)$ and $\angle(3)$ are equal, you can make an equation with their values as so:
$3x+10=4x-30$
You can solve this to find the value for x:
$3x+10=4x-30$
$(10+30)=(4x-3x)$
$40=x$
Now you can plug this value in to find the actual value of $\angle(1)$:
$\angle(1)=(3x+10)^{\circ}$
$\angle(1)=(3(40)+10)^{\circ}$
$\angle(1)=(120+10)^{\circ}$
$\angle(1)=130^{\circ}$
