Question 769887
<pre>
Converting from degrees to radians
90 deg = {{{pi/2}}} radians
180 deg = {{{pi}}} radians

Complement of an angle + angle = 90 deg or {{{pi/2}}} radians
Supplement of an angle + angle = 180 deg or {{{pi}}} radians

Complement of {{{2pi/9}}} = {{{pi/2 - 2pi/9 = 5pi/18}}} radians or 50 degrees
Supplement of {{{2pi/9}}} = {{{pi - 2pi/9 = 7pi/9}}} radians or 140 degrees
:)
</pre>