📐 Topic Summary
The Triangle Angle Sum Theorem states that the sum of the interior angles of any triangle is always 180 degrees. This theorem is fundamental in geometry and is used to find missing angles in triangles when other angles are known. Understanding this theorem allows you to solve many geometric problems related to triangles.
In essence, if you have a triangle with angles A, B, and C, then $A + B + C = 180^{\circ}$. This simple equation is a powerful tool for solving for unknown angles. Let's test your knowledge with the following practice quiz!
🧠 Part A: Vocabulary
Match the term with its definition:
| Term |
Definition |
| 1. Interior Angle |
A. A triangle with all angles less than 90 degrees. |
| 2. Obtuse Angle |
B. An angle greater than 90 degrees but less than 180 degrees. |
| 3. Acute Triangle |
C. An angle inside a shape. |
| 4. Right Triangle |
D. A triangle with one 90-degree angle. |
| 5. Triangle |
E. A closed shape with three sides and three angles. |
✍️ Part B: Fill in the Blanks
The Triangle Angle Sum Theorem states that the sum of the three interior angles of a triangle is always __________ degrees. Therefore, if two angles of a triangle are 60 degrees and 80 degrees, the third angle must be __________ degrees. This is because 60 + 80 + __________ = 180.
🤔 Part C: Critical Thinking
Explain how the Triangle Angle Sum Theorem can be used in real-world applications, providing at least one specific example.