INTRO

—

Complementary and supplementary angles are special pairs of angles 👯♀️.Check out our or explore our and sections to learn more about how to find the area of triangles and test your understanding.

__Co__mplementary angles are two angles that combine to form a $90_{∘}$

__co__rner.

__S__upplementary angles are two angles that combine to form a $180_{∘}$

__s__traight line.

Calculator

Lesson

Practice

You can also use the Quick Links menu on the left to jump to a section of your choice.

You can also use the Quick Links dropdown above to jump to a section of your choice.

CALCULATOR

—

## Complementary & Supplementary Angles Calculator

Are the two angles complementary or supplementary?

KEY STEPS

—

## How to Find Complementary & Supplementary Angles

Show steps for angles that are:If the two angles are If we know the measure of one of the two angles, we can use it to find the value of the missing angle.

### Step 1. Determine the total angle measure.

__co__mplementary or form a

__co__rner (right angle), then the total angle measure is $90_{∘}$.

### Step 2. Find the value of the unknown angle.

$given angle+unknown angleunknown angle =90_{∘}=90_{∘}−given angle $

LESSON

— Complementary and Supplementary Angles

## Complementary and Supplementary Angles

Complementary and supplementary angles problems come in a few different forms. Sometimes, you'll be given a diagram with one given angle and one unknown angle:

$25_{∘}$

$?$

__co__rner tells us the two angles are

__co__mplementary and add up to $90_{∘}$.

And if you see two angles on a

__s__traight line like this:$70_{∘}$

$?$

__s__upplementary and add up to $180_{∘}$.

PRACTICE

— Complementary and Supplementary Angles

## Practice: Complementary & Supplementary Angles

Question 1 of 10: Find the unknown angle:

$40_{∘}$

$?$

### Step 1. Determine the total angle measure.

What is the total angle measure?

CONCLUSION

—

Incredible job, look at you go! Thanks for checking out this lesson ☺️🙏. Where to next?

Leave Feedback