Ok, so
We got the following parallelogram:
We want to find the value of the angle BCD.
For this, remember that the sum of the internal angles of a parallelogram must be always equal to 360°.
So, we could write:
[tex]\begin{gathered} 2x+2x+x+x=360 \\ 6x=360 \\ x=\frac{360}{6} \\ x=60 \end{gathered}[/tex]
The value of x is equal to 60°. Now, the angle BCD is an angle that measures 2x degrees.
So, BCD measures 2*60, which is 120°.
