Search the courses, subjects, tracks, games and features, or jump straight to a page.
Learn it your way
A short class with Sarah and her students. The other ways are under More.
Sign up free to listen. Transcripts are free to read.
Today we're going to learn about angle relationships! Let's start with complementary angles. Can anyone tell me what complementary angles are?
Are they the angles that add up to 90 degrees?
Exactly right! Complementary angles sum to 90 degrees. For example, if one angle measures 25 degrees, what would its complement be?
It would be 65 degrees!
Great! Now, can anyone define supplementary angles?
I think they add up to 180 degrees!
Correct! So if you have a 110-degree angle, what angle would it need to pair with to be supplementary?
It would need another angle of 70 degrees!
Well done, everyone! Remember: Complementary = 90 degrees and Supplementary = 180 degrees. Let's move on!
Next, let’s look at adjacent angles. Who can explain what these are?
They share a common vertex and side but do not overlap.
Exactly! Can you think of a real-world example of adjacent angles?
Like the corners of a book!
Perfect! Now, what about linear pairs?
A linear pair is when two adjacent angles form a straight line, right?
That's correct. And remember, linear pairs are always supplementary. If one angle measures 45 degrees, the other must be 135 degrees. Let’s summarize: Adjacent angles share sides; linear pairs are adjacent and supplementary.
Now, let's finish up with vertically opposite angles. What happens when two lines intersect?
They create pairs of angles that are opposite to each other.
Right! And what do we know about the measures of these angles?
They are equal!
Exactly! If we have one angle measuring 70 degrees, the angle directly opposite will also measure 70 degrees. This is a fundamental property in geometry. Remember: Vertical angles are always equal. Let’s recap: Complementary adds to 90, supplementary adds to 180, adjacent share a side, linear pairs are adjacent, and vertical angles are equal.
Angles that sum to 90 degrees.
Angles that sum to 180 degrees.
Angles that share a common vertex and side.
Adjacent angles that form a straight line.
Equal angles formed when two lines intersect.
Example of complementary angles: 30° and 60°.
Example of supplementary angles: 110° and 70°.
Example of adjacent angles: Two angles formed by radiating from a point.
Example of linear pair: 45° and 135° are adjacent and form a straight line.
Example of vertically opposite angles: If two intersecting lines create one angle of 50°, the opposite angle also measures 50°.
To remember angles that complement and please, 90 degrees is the goal, no less, no tease!
Imagine two friends, Complement and Supplement, who always meet at the park. If Complement loves to play for 90 minutes, Supplement makes sure they spend a total of 180 minutes together.
C for Complementary = 90 degrees, S for Supplementary = 180 degrees.
AS: Adjacent & Supplementary, consider the sum! V for Vertically opposite means equal, they’re never done!
Term
Complementary Angles
Click to flip
Term
Supplementary Angles
Click to flip
Term
Adjacent Angles
Click to flip
Term
Linear Pair
Click to flip
Term
Vertically Opposite Angles
Click to flip
Two angles whose sum is 90 degrees.
Two angles whose sum is 180 degrees.
Angles with a common vertex and a common side but no common interior points.
Two adjacent angles whose non-common sides form a straight line.
Angles that are opposite each other when two lines intersect; they are equal.
This section covers the various relationships between angles, including complementary, supplementary, adjacent, linear pair, and vertically opposite angles.
In this section, we explore different types of angle relationships that arise in geometry. Complementary angles sum to 90 degrees, supplementary angles sum to 180 degrees, adjacent angles share a common vertex and side without overlapping, linear pairs are adjacent angles that form a straight line, and vertically opposite angles are equal when two lines intersect. Understanding these concepts is fundamental in solving geometric problems.
In geometry, angles can interact in several ways that reveal important relationships necessary for understanding complex designs and solving equations. This section introduces five primary types of angle relationships:
Complementary Angles: Two angles are complementary if the sum of their measures equals 90 degrees. For example, if one angle measures 30 degrees, the other must measure 60 degrees.
Supplementary Angles: Two angles are supplementary if their measures sum to 180 degrees. For instance, 110 degrees and 70 degrees are supplementary angles.
Adjacent Angles: These angles have a common vertex and a common side but do not overlap in any part of their interior space. An example would be the angles formed when two rays meet at a point.
Linear Pair: A linear pair consists of two adjacent angles whose non-common sides form a straight line. Thus, their measures always sum to 180 degrees, demonstrating the supplementary relationship.
Vertically Opposite Angles: When two lines intersect, they create pairs of vertically opposite angles. These angles are always equal, a property that can be proven through the angle addition postulate.
Understanding these relationships not only aids in geometry problem-solving but also enhances spatial reasoning and logical thinking skills.