∠∠BOC is less than 2/5 (2/5) of the complementary angle of∠∠∠∠ AOB.

∴∠boc=∠aoc+∠boa=2/5( 180-∠AOB)-5 = 67-2/5∠boa

∫∠AOC is smaller than∝∞∠ BOC 10.

∴∠aoc=90-∠BOC- 10 = 80-∠BOC = 80-(∠AOC+∠boa)

∴∠AOC = 25 °, boa = 30°。

② When OB is within ∠AOC.

∠∠BOC is less than 2/5 (2/5) of the complementary angle of∠∠∠∠ AOB.

∴∠ BOC =∠ AOC-∠ BOA = 2/5 (180-∠ Bao Er) -5 = 67-2/5∠ Bao Er.

∫∠AOC is smaller than∝∞∠ BOC 10.

∴∠aoc=90-∠BOC- 10 = 80-∠BOC = 80-(∠AOC-∠boa)

No answer

③OC is within ∠AOB.

∠∠BOC is less than 2/5 (2/5) of the complementary angle of∠∠∠∠ AOB.

∴∠boc=∠boa-∠aoc=2/5( 180-∠AOB)-5 = 67-2/5∠boa

∫∠AOC is smaller than∝∞∠ BOC 10.

∴∠aoc=90-∠BOC- 10 = 80-∠BOC = 80-(∠boa-∠AOC)

∴∠AOC = 45 °, boa = 80°。