Question

AB parallel DE Angle ABC 100 °, angle CDE =120 ° find theta

Answer 1

$\textit{ \textbf{ Hello Mate! }}$

<ODE + <XOC = 180° [ Interior consecutive < ]

<XOC = 180° - 120°

<XOC = 60°

<XOC = <BOC = 60° [ Vertically opposite < ]

<ABC + <CBO = 180° [ Linear pair]

<CBO = 180° - 100°

<CBO = 80°

<CBO + < BOC + BCO = 180° [Angle sum property]

80° + 60° + <BCO = 180°

<BCO = 40°

$\boxed{ \textsf{ Hence,\:angle BCO=40° }}$

$\texttt{ Have Great Future Ahead! }$