Question

Tick (✓) the correct answer:
The angles of a pentagon are x°, (x + 20)°, (x + 40)°, (x + 60)° and (x + 80)°. The smallest angle of the pentagon is
(a) 75°
(b) 68°
(c) 78°
(d) 85°

Answer 1

(b) 68°
​Sum of all the interior angles of a polygon with n sides = $\left(n-2\right)\times 180°$

$$\begin{gathered} \therefore (5-2)\times {180}^o=x+x+20+x+40+x+60+x+80 \\ \Rightarrow 540=5x+200 \\ \Rightarrow 5x=340 \\ \Rightarrow x={68}^o \end{gathered}$$