# A,B and C are the 3 points on the circle and O is the centre of the circle.If <OAB is 40°, <ABC is 120°,<BCO is y° and <COA is x°. Find the value of x° and y°?

Feb 16, 2018

y=80°˛ x=120°!

#### Explanation:

$O A = O B = O C = r$
∠ OAB=∠ ABO=40°
∠OBC=120°-40°=80°
y°=∠ BCO=∠ OBC=80°
∠COB=180°-2 \cdot 80°=20°
∠BOA=180°-2 \cdot 40°=100°
x°=∠COB+∠BOA=120°