Final: Isosceles Chase

Part of the Angles section of Coddy's Geometry journey. Lesson 61 of 62.

Use the matching side marks to identify the equal base angles. The apex angle is given by an expression. Add all three angle measures and set their sum equal to 180°.

Challenge

Hard

The triangle in the figure has apex (x + 50)° and one base angle of 45°.

$An isosceles triangle with apex x plus 50 degrees and a marked base angle of 45 degrees$

Find x.

Try it yourself

(x + 50) + (45 + 45) = 180

Solve for x

Test yourself

This lesson includes a short quiz. Start the lesson to answer it and track your progress.

All lessons in Angles

2Straight Lines and Supplements

Angles on a Line Supplementary Angles Three Angles on a Line Write the Equation Recap: Along the Line

5Around a Point

Angles Around a Point The Missing Angle Equal Slices Four Angles, One Point Recap: The Full Turn

8Transversal Problems

Both Angles Labeled Verticals Meet Parallels From Figure to Equation Alternate with Algebra Recap: Through the Strip

11The Exterior Angle

The Exterior Angle Using the Shortcut Two Roads, One Answer Exterior in the Wild Recap: Outside View

3Right Angles and Complements

Complementary Angles Finding the Complement Perpendicular Lines Equal Parts of a Corner Recap: The Right Corner

6The Angle Bisector

The Angle Bisector Bisected Expressions Bisecting a Straight Angle Recap: Split in Half

9Triangle Angle Sum

The 180 Rule Finding the Third Angle Two Unknown Angles Right Triangles Recap: The Budget

12Final Challenges

Final: The Angle Chase Final: Triangle Meets Line Final: The Full RoundFinal: Isosceles ChaseFinal: Master of Angles