ANSWER

EXPLANATION
Method 1
Vertically opposite angles are equal, therefore

This implies that,

We simplify to get,

Dividing through by 3 gives,

Also,

This implies that,

We simplify the right hand side to get,

We divide both sides both sides by 2 to get,



Method 2
Angles on straight line sums to 180°.

This implies that,




Also,






