BECE Mathematics 2020 Paper

ConceptsA triangle which has two of its sides equal is called an isosceles triangleProperties of Isosceles Triangle1. The two equal sides of an isosceles triangle are called the legs and the angle between them is called thevertex angle or apex angle.2. The side opposite the vertex angle is called the base and base angles are equal.3. The perpendicular from the vertex angle bisects the base and the vertex angle.Applying property 2 to redraw the triangle in the question gives us the diagram below: From the above properties, you will realize that angle $\mathrm{CBA}=\mathrm{BAC}=56^{\circ}$Applying the concept that says that angles on a straight line add up to $180^{\circ}$$\Rightarrow x+56=180$Make $x$ the subject$\; \Rightarrow x=180-56$$\; x=124$