In a parallelogram, opposite angles are congruent.
This means that the four angles of the parallelogram are:

Moreover, the sum of the interior angles of a polygon with n sides is 180(n-2). So, the sum of the interior angles of a parallelogram is 360.
This means

And since
, we have 
Answer:
6.2
Step-by-step explanation:
Actual value: 6.15636257
If f(x) = g(x), -3x+4 = 2, -3x = -2, x = 2/3