Question

Hi, can someone please solve this question with step by step explanation? I am really confused on this one

Answer 1

Step-by-step explanation:

angle COB+angle AOC=180°( linear pair )

angle COB +100°= 180°

angle COB= 80°

angle BOD= angle AOC(vertically opposite angle)

angle BOD = 100°

angle DOA= angle COB( vertically opposite angle)

angle DOB= 80°

Answer 2

Answer:

5) a:b = 5:7

let it be 5x and other be 7x

5x + 7x = 180°

=>12x = 180°

=>x=15 °