Answer:
x = 200
Explanation:
A rectangle (and any parallelogram) will always equal 360 degrees in angles. Technically, every angle has to equal 90 degrees for it to be a rectangle, just a side note.
Thus, 60 + 30 + 70 + x = 360
Solve for x.
60 + 30 + 70 + x = 360
160 + x = 360
x = 360 - 160
x = 200