For this case we have that the sum of the internal angles of a quadrilateral is 360 degrees.
As we are told that the pairs of sides are congruent we have:
[tex]7x + 11x + 7x + 11x = 360\\36x = 360\\x = \frac {360} {36}\\x = 10[/tex]
So, x = 10.
So:
[tex]7x = 7 (10) = 70 \ degrees\\11x = 11 (10) = 110 \ degrees[/tex]
Answer:
[tex]x = 10[/tex]
