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Verticals Meet Parallels

Part of the Angles section of Coddy's Geometry journey. Lesson 38 of 62.

Some marked pairs match none of the three letters. Then chain: trade an angle for its vertical twin (equal, from chapter 4) until a nameable pair appears. One trade is usually enough.

$A 75 degree angle above the top parallel and w degrees at the lower crossing$

The angle vertically opposite the marked 75° angle is also 75°. It is co-interior with w° between the parallel lines, so 75 + w = 180, giving w = 105.

Challenge

Medium

The 55° angle sits above the top parallel; x° sits at the lower crossing.

$A 55 degree angle above the top parallel and x degrees at the lower crossing$

Find x.

Try it yourself

x + 55 = 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 LabeledVerticals Meet ParallelsFrom 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 Round Final: Isosceles Chase Final: Master of Angles