(1)设该角为x度,则:
(90-x)-(180-x)*2/9=1
90-x-40+x*2/9=1
50-x*7/9=1
x*7/9=49
x=63(度)
答:该角为63度.
(2)∠COE=1/2∠BOE
∠AOC=180-∠COB=180-(∠COE+∠BOE)=180-(1/2∠BOE+∠BOE)
=180-3/2∠BOE
∠DOC=1/2∠AOC=1/2(180-3/2∠BOE)=90-3/4∠BOE
∠DOE=∠DOC+∠COE=72
(90-3/4∠BOE)+1/2∠BOE=72
90-1/4∠BOE=72
1/4∠BOE=18
∠BOE=72