a) Ta có: \(\widehat{AOn}+\widehat{mOn}=90^0\)
\(\widehat{BOm}+\widehat{mOn}=90^0\)
Do đó: \(\widehat{aOn}=\widehat{bOm}\)
b) Ta có: \(\widehat{aOn}+\widehat{bOn}=150^0\)
\(\Leftrightarrow\widehat{aOn}=150^0-90^0=60^0\)
\(\Leftrightarrow\widehat{mOn}=90^0-60^0=30^0\)