Question

If $\overline{AD}$ and $\overline{BC}$ are parallel, then calculate the value of $x$.

• A. ${60}^o$
• B. ${70}^o$
• C. ${80}^o$
• D. ${110}^o$

Answer 1

The correct option is B ${70}^o$

Since line $AD$ is parallel to line $BC$, $\angle BCD+\angle ADC={180}^o$

$\Rightarrow \angle ADG+70+60=180$

$\Rightarrow \angle ADG={50}^o$

Now, in $\Delta ADG,\angle ADG+\angle AGD+\angle DAG={180}^o$

$\Rightarrow {60}^o+{50}^o+x={180}^o$

$\Rightarrow x={70}^o$