Question

In the given figure, AB = AC, $\angle ABE={120}^{\circ }$ The value of $x$ = ___

• A. ${65}^{\circ }$
• B. ${70}^{\circ }$
• C. ${60}^{\circ }$
• D. ${55}^{\circ }$

Answer 1

The correct option is C

${60}^{\circ }$

(i) $\angle ABC={180}^{\circ }-{120}^{\circ }={60}^{\circ }$.......(linear pair)

(ii) $△ABC$ is isosceles ............(given AB = AC )

(iii) $\therefore \angle ABC=\angle ACB={60}^{\circ }$

(iv) $\angle x={180}^o-(\angle ABC+\angle ACB)$

(v) $\angle x={180}^o-({60}^o+{60}^o)$

(vi) $\angle x={180}^o-{120}^o$

(vii) $\angle x={60}^o$