Question

Calculate the value of $x$ in the above figure.

• A. ${100}^o$
• B. ${70}^o$
• C. ${120}^o$
• D. ${125}^o$

Answer 1

The correct option is A ${100}^o$

Since angles ${2y}^o$ & $4y^o$ form a linear pair, they must add up to ${180}^o$

So, $6y={180}^o$ or $y={30}^o$

Also, $4y=x+20$, since these are vertically opposite angles.

$\therefore 120=x+20$

$\therefore x={100}^o$