Question

The measure of $\angle ABD$ in the figure given below is${}^o$.

Answer 1

The given figure is,
We can observe from the figure,
$\bullet$ $m\angle DBC={60}^o$
$\bullet$ $\angle ABD$ and $\angle DBC$ form a linear pair.

$\therefore$ $m\angle ABD+m\angle DBC={180}^o$
$\Rightarrow$ $m\angle ABD+{60}^o={180}^o$
Subtracting ${60}^o$ from both sides,
$\Rightarrow$ $m\angle ABD+{60}^o-{60}^o={180}^o-{60}^o$
$\Rightarrow$ $m\angle ABD={120}^o$

Hence, the measure of $\angle ABD$ is ${120}^o$.