Answer:
They are in A. P so the sum will be 2380
The answer should be x=60. ABD are an equilateral triangle all the angles must add up to 180. 60*3=180. Also if you have a protractor you can measure the angle C, the 60 degrees part and measure it against A, D and B. Hope this helps.
Answer: The answer is in the first image.
Explanation: The explanation is in the second image.