For this case we have that by definition, a flat angle is the space included in an intersection between two straight lines whose opening measures 180 degrees.
Now, according to the figure we have that from V to S there are 180 degrees, like this:
[tex]5x + 25x + 30 = 180[/tex]
We add similar terms:
[tex]30x + 30 = 180[/tex]
Subtracting 30 from both sides of the equation:
[tex]30x = 150[/tex]
Divide by 30 on both sides of the equation:
[tex]x = \frac {150} {30}\\x = 5[/tex]
Answer:
[tex]x = 5[/tex]
