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**In This Unit of Study…**

Students will explore angles as an attribute of two-dimensional figures. They will identify and classify angles as acute, right, obtuse, straight, or reflex. Students will understand that the vertex of an angle is located at the center of a circle; it is from this point that two rays can create angle measurements. They are introduced to a new type of measurement when learning to measure angles. Students will learn that angles are measured by the “turning distance” between two rays, which use increments of 1/360 of a circle, or a 1° (degree) angle. In addition, students will estimate angle measures and practice measuring angles by using a protractor. This includes aligning the vertex, the zero edge, and the ray properly to tell the degrees of an angle. Fourth-grade students will learn to read, document, and draw angles in the proper mathematical format. This scope helps students discern that angle measure is additive. Through decomposing angles into nonoverlapping parts, students will see that the angle measure of the whole is the sum of the angle measures of the parts. In conclusion, students will solve real-world and mathematical problems to find unknown angles, and they will write an equation to represent the unknown.

**B.E.S.T. Benchmarks:**

**MA.4.GR.1.1**Informally explore angles as an attribute of two-dimensional figures. Identify and classify angles as acute, right, obtuse, straight or reflex.**MA.4.GR.1.2**Estimate angle measures. Using a protractor, measure angles in whole-number degrees and draw angles of specified measure in whole-number degrees. Demonstrate that angle measure is additive.**MA.4.GR.1.3**Solve real-world and mathematical problems involving unknown whole-number angle measures. Write an equation to represent the unknown.

**Overarching Key Concepts:**

- Identify and Classify Angles
- Estimate and Measure Angles
- Determine Unknown Angle Measures