Объяснение:
∠ВAE =180-∠AEB-∠B=180-78-90=12°,
∠C=180-∠A-∠B=180-78-69=33°
∠DBE=90-∠C=90-33=57°
∠ABO=78-∠DBE (57) =21°
∠ AOB=180°-(∠BAE+∠ABO)=180-(12+21)=147°
Объяснение:
∠ВAE =180-∠AEB-∠B=180-78-90=12°,
∠C=180-∠A-∠B=180-78-69=33°
∠DBE=90-∠C=90-33=57°
∠ABO=78-∠DBE (57) =21°
∠ AOB=180°-(∠BAE+∠ABO)=180-(12+21)=147°