Question

Find the value of x${}^o$ in the adjacent figure

Answer 1

Given $\angle ACB={40}^o$
By the theorem angle made by the arc AB at the centre
$\angle AOB=2\angle ACB=2\times {40}^o={80}^o$
$\because x^o+\angle AOB={360}^o$
Therefore $x^o={360}^o-{80}^o={280}^o$