What Are Complementary and Supplementary Angles?

TL;DR

Complementary angles are two angles that sum to 90 degrees, while supplementary angles are those that add up to 180 degrees. Additionally, adjacent angles share a common side, and perpendicular angles are formed by right angles at 90 degrees. Understanding these relationships is essential for mastering geometry.

Transcript

Let's say I have an angle ABC, and it looks something like this. So its vertex is going to be at B. Maybe A sits right over here, and C sits right over there. And then also let's say that we have another angle called DBA. I want to have the vertex once again at B. So let's say it looks like this. So this right over here is our point D. That is our ... Read More

Key Insights

• 🔺 Angles that share a side are called adjacent angles.
• 🪜 Complementary angles add up to 90 degrees.
• 🪜 Supplementary angles add up to 180 degrees.
• 🔺 Perpendicular angles are formed by a right angle of 90 degrees.
• 📏 Two angles that form a straight line are called straight angles.
• 🔺 Complementary angles are adjacent angles that form a right angle.
• 🔺 Supplementary angles are adjacent angles that form a straight angle.

Questions & Answers

Q: What are adjacent angles?

Adjacent angles are angles that share a common side. In the provided content, angle DBA and angle ABC are adjacent angles because they both share the ray BA.

Q: What are complementary angles?

Complementary angles are two angles that add up to 90 degrees. In the content, angle DBA and angle ABC are complementary angles because their measures add up to 90 degrees.

Q: What are supplementary angles?

Supplementary angles are two angles that add up to 180 degrees. An example given in the content is angle MNO and angle XYZ, whose measures add up to 180 degrees, making them supplementary angles.

Q: What are perpendicular angles?

Perpendicular angles are formed when two lines or line segments intersect to create a right angle, which measures 90 degrees. In the content, it is mentioned that line segment DB is perpendicular to line segment BC.

Summary & Key Takeaways

• Angles that share a side are called adjacent angles.

• When two angles add up to 90 degrees, they are complementary angles.

• Angles that add up to 180 degrees are called supplementary angles.

• Perpendicular angles are formed when a right angle is created between two lines or line segments.