Question 465856
Complementary angles add up to 90 degrees (when you put them together, they make a right angle).  If I call the angle you're looking for x, then {{{89+x=90}}}...subtract 89 on both sides, and your missing angle is 1 degree.


I know the question didn't ask this, but another term you'll run into is "supplementary angle".  Supplementary angles add to 180...you'd do the exact same thing we just did, except it would equal 180 instead of 90.