Question

In the following fig. $\angle 1={25}^o$ and $\angle 3={35}^o$. Find $\angle 5$.

• A. ${120}^o$
• B. ${60}^o$
• C. ${170}^o$
• D. ${75}^o$

Answer 1

The correct option is A ${120}^o$

$\angle 1=\angle 4$ (vertically opposite angle)
$\because \angle 1={25}^o$
$\therefore \angle 4={25}^o$
$\angle 3=\angle 6$ (vertically opposite angle)
$\because \angle 3={35}^o$ (given)
$\therefore \angle 6={35}^o$
$\angle 4+\angle 5+\angle 6={180}^o$ (Linear pair)
${25}^o+\angle 5+{35}^o={180}^o$
$\therefore \angle 5={180}^o-{60}^o$
$={120}^o$