Question

The angles of a quadrilateral are ${110}^{\circ },$ ${72}^{\circ },$ ${55}^{\circ }$ and $x^{\circ }$. Find the value of x.

Answer 1

$\because$ Sum of four angles of quadrilateral is ${360}^{\circ }$.
$\therefore {110}^{\circ }+{72}^{\circ }+{55}^{\circ }+x^{\circ }={360}^{\circ }\Rightarrow {237}^{\circ }+x^{\circ }={360}^{\circ }\Rightarrow x^{\circ }={360}^{\circ }-{237}^{\circ }={123}^{\circ }\therefore x={123}^{\circ }$ Ans.