In the given figure, AB is the diameter of the circle with center O. If ∠BOD = 15° & ∠EOA = 85°, then find the value of ∠ECA.

Question: In the given figure, AB is the diameter of the circle with center O. If ∠BOD = 15° & ∠EOA = 85°, then find the value of ∠ECA.Solution:∠EOA = 85°, ∠BOD = 15°∠EOD = 180° - (85° + 15°) = 80°In ΔOED,OE = OD (radii)∠OED = ∠ODE = 50°In ΔOEC, ∠EOC = 80°+15° = 95°, ∠OEC =50°∴ ∠ECA = 180°- (95 + 50°) = 35°