Develop an understanding of angles and angle measurement.
Understand angles as geometric shapes that are formed wherever two rays share a common endpoint, and are measured in degrees.
Measure and sketch angles in whole-number degrees using a protractor.
Solve addition and subtraction problems to find unknown angles on a diagram in real-world and mathematical problems.
Step 1: Lesson Standards & Learning Goals
In this standard, students explore angles and their properties. An angle is formed by two rays that share an endpoint and is measured with reference to the degrees of a circle.
Students will be able to identify three types of angles: right angle, acute angle, and obtuse angle.
Students will learn to measure and sketch angles using a protractor. Students should also have an understanding of benchmark angles such as 45º, 90º and 180º.
Students will explore the additive nature of angle measurements and solve one- and two-step addition and subtraction problems where an angle measure is missing. When an angle is decomposed into non-overlapping parts, the angle measure of the whole is the sum of the angle measures of the parts.
The terms complimentary, supplementary, and adjacent may come up in discussion, but students are not responsible for knowing these terms until middle school. See Unpacking Document for further information.
What is an angle, and how is it measured?
What tools can we use to measure angles accurately?
How do we classify angles based on their measures (acute, obtuse, right, straight)?
How does the concept of degrees relate to measuring angles?
What strategies can we use to estimate angles without measuring tools?
What are the properties used to identify the right angle, acute angle, and obtuse angle?
What are some strategies to solve one- and two-step addition and subtraction problems where an angle measure is missing?
Acute angle
Angle
Benchmark angles
Decompose
Degree
Obtuse angle
Perpendicular (right angles)
Protractor
Ray
Right angle
Straight angle
Vertex/vertices
Recognize angles as geometric shapes that are formed wherever two rays share a common endpoint, and are measured in degrees.
Identify three types of angles: right angle, acute angle, and obtuse angle.
Measure and sketch angles in whole-number degrees using a protractor.
Understand benchmark angles such as 45º, 90º and 180º.
Use a right angle as a benchmark to determine if an angle is acute, obtuse, or right.
Recognize angle measure as additive.
Solve one- and two-step addition and subtraction problems where an angle measure is missing.
Angles are geometric shapes that are formed wherever two rays share a common endpoint, and are measured in degrees.
An angle is measured with reference to a circle with its center at the common endpoint of the rays.
An angle that turns through 1/360 of a circle is called a “one-degree angle” and can be used to measure angles.
An angle that turns through n one-degree angles has an angle measure of n degrees.
When an angle is decomposed into non-overlapping parts, the angle measure of the whole is the sum of the angle measures of the parts.
Step 2: Assessment
NC.4.MD.6 - CO - Howell - Mar. 8, 2023
NC.4 - Cluster 8 Review - CO - Howell - Mar. 6, 2023
NC.4 Benchmark Review Practice - CO - Howell - Mar. 31, 2023
Step 3: Lesson Instructions
Exploration or Experience
Provide students with a protractor and have them discuss their notices and wonders with a partner. Give students an opportunity to experiment with the protractor before giving them instructions on how to use the tool.
Read Aloud
Video Clip
Tools 4 NC Teachers
Cluster 8 Lessons
Math Expressions - (Barnes and Hearne) - Standards Alignment
Motivation Math
Think Up! Math
Khan Academy - 4th Grade Math
Eureka Math/Engage NY Free Resources
Embarc Online (Eureka Math) -
Zearn Math - Online Support Practice for Eureka Math (Requires free account)
Khan Academy Eureka Math Grade 4
North Carolina Collaborative for Mathematics Learning - Grade 4 Instructional Framework
NCDPI Resources
Thinking Blocks - Word Problem Practice with Bar Diagrams
YouTube Videos
Fact Practice
