Question 128982
An angle plus its supplement measures 180 degrees, and an angle plus its complement measures 90 degrees.


The compliment of an angle would be something like "My, you are a very pretty little angle!"  "My, you are a cute little angle!" would be a horrible pun.


Measure of the angle: x
Measure of the supplement of the angle: 180 - x
Measure of the complement of the angle: 90 - x


Therefore:


{{{(180-x)+(90-x)=210}}}


{{{-2x+270=210}}}


{{{-2x=210-270}}}


{{{-2x=-60}}}


{{{x=30}}}


The supplement of an angle that measures 30 degrees measures 150 degrees, and the complement of an angle that measures 30 degrees measures 60 degrees.  150 plus 60 equals 210.  Answer checks.