Question

In the given figure 'O' is the centre of the circle and AB, CD are equal chords. If $\angle AOB={70}^o$. Find the angles of the $△OCD$.

Answer 1

Consider triangle $AOB$ and triangle $OCD$

$OA=OB=OC=OD=radius$

$\angle AOB=\angle DOC=70$

In $△OCD$

$OD=OC$

$\angle ODC=\angle OCD$

$\angle OCD+\angle ODC+\angle DOC=180$

$2\angle OCD={180}^o-{70}^o$

$\angle OCD={55}^o=\angle ODC$