# Michael is always getting complementary angles confused with supplementary angles. He can't remember which means that the sum of the measures of the angles is 90 degrees and which is 180 degrees. What is a trick to help Michael remember?

Mar 20, 2018

We know

Complementary of ${\theta}^{\circ} = {90}^{\circ} - {\theta}^{\circ}$

Suplementary of ${\theta}^{\circ} = {180}^{\circ} - {\theta}^{\circ}$

• Confusion may be avoided if it is remembered that the angle to be added with an angle to complete a right angle is Complementary.

The Mnemonic:

$\textcolor{m a \ge n t a}{\text{Complementary Completes a Right Angle}}$

• Otherwise in alphabetical order $\textcolor{red}{\text{'C' comes before 'S'.}}$
So to get Complementary angle we are to subtract the given angle from ${90}^{\circ}$ which is less than ${180}^{\circ}$ from which the given angle is to be subtracted to get its Suplementary angle.