The five interior angles of a pentagon are x°, $(x + 20)^\circ$, $(x + 40)^\circ$, $(x + 60)^\circ$ and $(x + 80)^\circ$. What is the largest angle?

Explanation

1. 01

   Angle sum of a pentagon = $(5 - 2) \times 180^\circ = 540^\circ$.

2. 02

   $5x + 200 = 540$, so $x = 68$.

3. 03

   Largest angle = $68 + 80 = 148^\circ$.