Question

Help? Picture attached!

Answer 1

AD subtends an angle of 30 at the center, right? Not at O?

Answer 2

I'm weak in geometry :(

Answer 3

I am too, that's why I'm here haha.

Answer 4

Would you mind marking the angle clearly? i can't identify which 30 and which is 20... :(

Answer 5

AD= 30, and angle A is 20

Answer 6

Is that all info you have ? and what is m the question mentioned?

Answer 7

I'm not sure what's it's asking, and that's all of the information :/

Answer 8

well what i can help with is:

arc(ADCB) = 180°

arc(AD) =30°
arc(BC) = 2*20 = 40°

so arc(DC) = 180-(30+40) = 110°

now you have arc(DC) and there must be a formula to calculate angle(DOC)

Answer 9

i found the formula of interior angles :D
m(DOC) = [arc(AB)+arc(DC)]/2= [180+110]/2 =145°