Question 1034730
<pre>
The formula for the sum of the interior angles of an n-sided
polygon is {{{(n-2)*"180°"}}}.  Add them up and set equal t
the formula with n=9, since a nonagon has 9 sides and 9
interior angles. 

{{{3x+15+2x+30+3x+10+2x+55+2x+60+2x-35+3x-5+x+40+2x+70=(9-2)*180}}}

Solve for x.

Get x = 51°

{{{3x+15}}}{{{""=""}}}{{{3("51°")+"15°")}}}{{{""=""}}}{{{"153°"+"15°"}}}{{{""=""}}}{{{"168°"}}}
{{{2x+30}}}{{{""=""}}}{{{2("51°")+"30°")}}}{{{""=""}}}{{{"102°"+"30°"}}}{{{""=""}}}{{{"132°"}}}
{{{3x+10}}}{{{""=""}}}{{{3("51°")+"10°")}}}{{{""=""}}}{{{"153°"+"10°"}}}{{{""=""}}}{{{"163°"}}}
{{{2x+55}}}{{{""=""}}}{{{2("51°")+"55°")}}}{{{""=""}}}{{{"102°"+"55°"}}}{{{""=""}}}{{{"157°"}}} 
{{{2x+60}}}{{{""=""}}}{{{2("51°")+"60°")}}}{{{""=""}}}{{{"102°"+"60°"}}}{{{""=""}}}{{{"162°"}}} 
{{{2x-35}}}{{{""=""}}}{{{2("51°")-"35°")}}}{{{""=""}}}{{{"102°"-"35°"}}}{{{""=""}}}{{{"67°"}}} 
{{{3x-5}}}{{{""=""}}}{{{3("51°")-"5°")}}}{{{""=""}}}{{{"153°"-"5°"}}}{{{""=""}}}{{{"148°"}}} 
{{{x+40}}}{{{""=""}}}{{{"51°"+"40°")}}}{{{""=""}}}{{{"91°"}}} 
{{{2x+70}}}{{{""=""}}}{{{2("51°")+"70°")}}}{{{""=""}}}{{{"102°"+"70°"}}}{{{""=""}}}{{{"172°"}}}

Edwin</pre>