waecmaths question:
Find the value of x in the diagram

Option A:
50o
Option B:
60o
Option C:
70o
Option D:
80o
waecmaths solution:
$\begin{align} & \angle BD{{G}_{reflex}}+\angle BD{{G}_{acute}}={{360}^{\circ }}\text{ }\!\!\{\!\!\text{ Angle at a point }\!\!\}\!\!\text{ } \\ & \text{26}{{\text{0}}^{\circ }}+\angle BD{{G}_{acute}}={{360}^{\circ }} \\ & \angle BD{{G}_{acute}}={{100}^{\circ }} \\ & \angle GDE=\angle FGD\text{ }\!\!\{\!\!\text{ alternate angles }\!\!\}\!\!\text{ } \\ & \angle BD{{G}_{acute}}=\angle GDE+\angle BDE \\ & {{100}^{\circ }}={{30}^{\circ }}+\angle BDE \\ & \angle BDE={{70}^{\circ }} \\ & x=\angle ABD=\angle BDE={{70}^{\circ }}\text{ }\!\!\{\!\!\text{ alternate angles }\!\!\}\!\!\text{ } \\\end{align}$
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