HowStuffWorks on MSN6 个月
What Are Supplementary Angles?
To find the supplementary second angle to the given angle, simply subtract 130 from 180 degrees. If you deduced that the unknown angle is 50 degrees, you are right on target . Now That's Interesting ...
Angles that add together to make a straight line are called supplementary angles. If you know one supplementary angle you can subtract it from 180° to find a missing angle.