Math with Mr. J: Finding the Missing Angle of a Triangle

Key Concept

• Sum of Angles in a Triangle: Always equals 180°.
  • Important for solving problems involving missing angles in triangles.

Example 1

• Given: Triangle with angles of 98° and 31°; missing angle represented by X.
• Equation Setup:
  • 98° + 31° + X = 180°
• Solving for X:
  • Add known angles: 98° + 31° = 129°
  • Substitute into equation: 129° + X = 180°
  • Isolate X by subtracting 129° from both sides:
    • X = 180° - 129°
    • X = 51°
• Result: Missing angle is 51°.

Example 2

• Given: Triangle with angles of 90° and 24°; missing angle represented by X.
• Equation Setup:
  • 90° + 24° + X = 180°
• Solving for X:
  • Add known angles: 90° + 24° = 114°
  • Substitute into equation: 114° + X = 180°
  • Isolate X by subtracting 114° from both sides:
    • X = 180° - 114°
    • X = 66°
• Result: Missing angle is 66°.

Conclusion

• Process: Add the given angles and subtract their sum from 180° to find the missing angle.
• This method involves setting up and solving an equation based on the 180° rule for triangles.

Video Conclusion

• Presented method is a straightforward way to find missing angles using basic addition and subtraction.
• Aimed at reinforcing the understanding of the triangle angle sum property.

End Note

• Objective: Help viewers grasp the concept of finding missing angles in triangles efficiently.
• Thank you message to viewers for watching the tutorial.