NC.4.G.2
Classify quadrilaterals and triangles based on angle measure, side lengths, and the presence or absence of parallel or perpendicular lines
Embedded Files
Step 1: Lesson Standards & Learning Goals
This standard calls for students to sort and classify quadrilaterals and triangles based on parallelism, perpendicularity, the lengths of sides, and angle types.
Triangles: Students should be able to use side length to classify triangles as equilateral, isosceles, or scalene; and can use angle size to classify them as acute, right, or obtuse. They then learn to cross-classify, for example, naming a shape as a right isosceles triangle.
Quadrilaterals: Students should be able to use the relationships between sides (parallel and perpendicular) and side lengths to classify quadrilaterals. Students are expected to know the characteristics of: quadrilateral, trapezoid, parallelogram, rectangle, square, and rhombus. While working with quadrilaterals, students’ experiences with drawing and identifying right, acute, and obtuse angles support them in classifying two-dimensional figures based on specific angle measurements. They use the benchmark angles of 90°, 180°, and 360° to approximate the measurement of angles.
Note: Students are not expected to know the sum of the interior angles of a triangle or a quadrilateral in Grade 4. The notion of congruence (“same size and same shape”) may be part of classroom conversation, but the concepts of congruence and similarity do not appear in standards until middle school. North Carolina has adopted the exclusive definition for a trapezoid. A trapezoid is a quadrilateral with exactly one pair of parallel sides.
Sample Essential Questions
Sample Essential Questions
Vocabulary
Vocabulary
How do we classify two-dimensional figures based on their properties?
How do we use parallel and perpendicular lines to classify triangles and quadrilaterals?
How do angles of different sizes contribute to the classification of geometric figures?
What are some strategies for identifying parallel or perpendicular lines within geometric shapes?
What are some strategies for naming triangles?
Acute angle
Acute triangle
Angle
Attribute
Degrees
Equilateral triangle
Isosceles triangle
Obtuse angle
Obtuse triangle
Parallel lines
Parallelogram
Perpendicular lines
Polygon
Quadrilateral
Rectangle
Regular polygon
Rhombus
Right angle
Right triangle
Scalene triangle
Square
Trapezoid
Triangle
Two-dimensional figure
Students will be able to...
Students will be able to...
Use attributes to identify quadrilaterals and triangles.
Identify examples and non-examples of quadrilaterals in a given category.
Identify triangles using side lengths and angle names.
Distinguish a trapezoid from other quadrilaterals.
Students will know...
Students will know...
The properties of geometric figures help classify them based on the presence or absence of parallel or perpendicular lines.
The characteristics of angles contribute to the classification of geometric shapes.
Shapes may have common attributes but may be categorized in different ways based on their properties.
A trapezoid is a special quadrilateral with exactly one pair of parallel sides.
The side lengths (isosceles, equilateral, scalene) and angles (acute, right, obtuse) can be used to name triangles.
A right angle measures exactly 90°, a straight line measures 180°, and a full circle measures 360°.
Step 2: Assessment
Mastery Connect
Mastery Connect
NC.4.G.2 - CO - Howell - Mar. 8, 2023
NC.4 - Cluster 8 Review - CO - Howell - Mar. 6, 2023
Step 3: Lesson Instructions
Possible Activating Strategies
Possible Activating Strategies
Read Aloud
Exploration or Experience / Graphic Organizer
Provide students with two examples of quadrilaterals or triangles. Have them compare and contrast the shapes using a Venn diagram.
Read Aloud
Teacher Resources
Teacher Resources
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
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