Degrees and the Full Turn

Part of the Angles section of Coddy's Geometry journey. Lesson 3 of 59.

A full turn is 360°. A straight line is half a turn, so it is 180°. A quarter turn is 90°, like the corner of a page.

Angles have names by their size:

Acute: less than 90°.
Right: exactly 90°. It has a small square in the corner.
Obtuse: more than 90° and less than 180°.
Straight: exactly 180°.

$An acute angle of 40 degrees, a right angle marked with a square, and an obtuse angle of 120 degrees$

Challenge

A pizza is cut into 8 equal slices. All the slices meet at the middle. Three slices side by side make an angle of x° at the middle. Find x. Write it as x = a number. Then press Check.

Start the lesson to read it in the interactive player and track your progress.

All lessons in Angles

1Meet the Angle

Your First Angle Angles on a LineDegrees and the Full TurnAcross the Crossing

4Vertical Angles

Two Lines Cross Vertical Angles Are Equal Solving with Verticals All Four Angles Recap: At the Crossing

7Parallels and Transversals

Parallel Lines Corresponding Angles Alternate Angles Co-interior Angles Which Rule Is It Recap: The Three Pairs

10Isosceles and Equilateral

Base Angles Are Equal Finding the Apex Which Angles Match Equilateral Angles Isosceles at Work Recap: Twin Corners

2Naming and Equations

Adding Adjacent Angles 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

8Angle Chases

Verticals Meet Parallels Is There Enough?From Figure to Equation Both Angles Labeled 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

The Square Mark Complementary Angles Perpendicular Lines Finding the Complement 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