A nonagon has angles that measure 155°, 130°, 120°, 150°, 165°, 135°, 125°, 140°, and n. What is n?

A nonagon has angles that measure 155°, 130°, 120°, 150°, 165°, 135°, 125°, 140°, and n. What is n?

$\begin{array}{lcl} \text{All angles } &=& 180^{\circ}\cdot 9 -360^{\circ} \\ &=& 180^{\circ}\cdot ( 9 - 2 ) \\ &=& 180^{\circ}\cdot ( 7 ) \\ &=& 1260^{\circ} \\ \end{array}$

$\begin{array}{lcl} n &=& 1260^{\circ} - ( 155^{\circ} + 130^{\circ} + 120^{\circ} + 150^{\circ} + 165^{\circ} + 135^{\circ} + 125^{\circ} + 140^{\circ} ) \\ n &=& 1260^{\circ} - 1120^{\circ} \\ n &=& 140^{\circ} \\ \end{array}$