>>14181549Summing up the angled in the bottom 2 edges gives you that the top edge of the big triangle must have an angle of 20 degrees.
Then the edge at D of the EDB spans an angle of 180 - 40 = 140 degrees
Then the edge at D of the BDA triangle has an angle of 180 - (60+80) = 40 degrees
Then the angle at D of the small triangle where x is is 140 - 40 = 100 degrees
Then the other angle in the small triangle where x is is 180 -(70+60) = 50 degrees
Finally, x = 180-(100+50) = 30 degres
