Given:
Consider the below figure attached with this question.
[tex]m\angle 3=(x+30)^\circ[/tex] and [tex]m\angle 4=(2x-80)^\circ[/tex].
To find:
The measure of angle 3.
Solution:
From the below figure it is clear that, angle 3 and angle 4 are vertically opposite angles.
We know that, vertically opposite angles are always equal. So,
[tex]m\angle 3=m\angle 4[/tex]
[tex](x+30)^\circ=(2x-80)^\circ[/tex]
[tex]x+30=2x-80[/tex]
[tex]x-2x=-30-80[/tex]
[tex]-x=-110[/tex]
[tex]x=110[/tex]
Now,
[tex]m\angle 3=(110+30)^\circ[/tex]
[tex]m\angle 3=140^\circ[/tex]
Therefore, the measure of angle 3 is 140 degrees.
