Lesson objective: Understand that the rotatation of 1/360 of a circle is a 1º angle.

Students bring prior knowledge of partitioning shapes into equal areas and expressiong those areas as unit fractions of a whole from 3.G.2. This prior knowledge is extended to partitioning circles into equal areas, from a center point, as students learn to express the amount of rotation in degrees. A conceptual challenge students may encounter is angular measurement.

The concept is developed through work with circles, which can be used to show 360º or one complete rotation.

This work helps students deepen their understanding of equivalence because 1/360 of a circle is the same as 1º.

Students engage in Mathematical Practice 3 (Construct viable arguments and critique the reasoning of others) as they consider the strategies and understandings of their peers and develop justifications for the reasoning that leads to their own solution.

**Key vocabulary:**

- angle
- degree
- rotation

**Special materials needed:**

- copy of Ferris wheel from the task