Nilai y adalah pakai cara

Sudut DOC + COB + BOA berpelurus
180 = (2x-6) + (x+15) + (x-9)
180 = 4x
x = 45°

Sudut BOA + AOE berpelurus
180 = (2x -6) + (3y-12)
180 = (90-6) + (3y - 12)
180 = 3y + 84 - 12
3y = 180 - 72
3y = 108
y = 36° [B]

y = 36 (b)

(2x - 6) + (3y - 12) = 180
(2.45 - 6) + (3y - 12) = 180
90 - 6 + 3y - 12 = 180
72 + 3y = 180
y = (180 - 72) : 3
y = 108 : 3
y = 36