Question

The value of $x$ in the given diagram is ?

• A. ${130}^o$
• B. ${140}^o$
• C. ${150}^o$
• D. ${160}^o$

Answer 1

Answer: (B)

${140}^o$

We know, by angle sum property, the sum of angles of a quadrilateral is ${360}^o$.
The given angles are ${70}^o,{60}^o,{90}^o,x$. ......[Linear pairs are supplementary]
Then, ${70}^o+{60}^o+{90}^o+x={360}^o$.

Therefore, the unknown angle is:

$\Rightarrow$ ${360}^o-({70}^o+{60}^o+{90}^o)=x^{\circ }$

$\Rightarrow$ $x^o={360}^o-{220}^o={140}^{\circ }$.

Therefore, the unknown angle is $x^o={140}^o$.

Hence, option $B$ is correct.