Question

Find the angle measure x in the following figures:
[4 marks]

(a) (b)

Answer 1

Using angle sum property of a quadrilateral,
${50}^{\circ }+{130}^{\circ }+{120}^{\circ }+x={360}^{\circ }$ ----[1 mark]
$\Rightarrow {300}^{\circ }+x={360}^{\circ }$
$\Rightarrow x=360-300$
$\Rightarrow x={60}^{\circ }$ ----[1 mark]


(b) Using angle sum property of a quadrilateral,
${90}^{\circ }+{60}^{\circ }+{70}^{\circ }+x={360}^{\circ }$ ----[1 mark]
$\Rightarrow {220}^{\circ }+x={360}^{\circ }$
$\Rightarrow x={360}^{\circ }-{220}^{\circ }$
$\Rightarrow x={140}^{\circ }$ ----[1 mark]