Question

$AB\parallel DE$. Find the measure of $\angle AOD$.

Answer 1

Draw $MN$ such that

$MN\parallel AB\parallel DE$

$\angle AOM=\angle OAB={30}^o$ (Alternate angle)

$\angle MOD=\angle ODE={70}^o$ (Alternate angle)

$\therefore \angle AOD=\angle AOM+\angle MOd$

$={30}^o+{70}^o$

$=100$

$\therefore \angle AOD={100}^o$