Virginia SOL 3.MG.4.f
The Standard
Combine no more than three polygons, where each has three or four sides, and name the resulting polygon (triangles, quadrilaterals, pentagons, hexagons, octagons).
Virginia Standards of Learning for Mathematics · The student will identify, describe, classify, compare, combine, and subdivide polygons.
Teacher's field guide
What This Standard Means
What Students Need to Do
- Students arrange up to three triangles or quadrilaterals so complete sides touch. They ignore shared interior edges, count the straight sides on the outside boundary, and name the resulting polygon.
What Mastery Looks Like
- A student can join given pieces without gaps or overlaps, trace the outside boundary, and count each side correctly. They ignore shared interior edges and name the new polygon from its number of outside sides.
Common Misconceptions
- Students may count all sides of the original pieces, including shared edges, instead of counting only the outline. They may count collinear segments as separate sides when an interior line meets the boundary. They may name the figure by its pieces rather than its outside sides.
How to Assess It
- Give each student two equal paper squares and one matching triangle. Say, “Make a rectangle with the squares, attach the triangle to one short end, then trace, count, and name the outline.”
Lesson moves
Ways to Teach It
Give students paper triangles and quadrilaterals to join edge to edge, trace the outside boundary, count its sides, and name the new polygon.
Show a composite figure and ask students which segments count as outside sides and why the interior segments do not count.
Play Build and Name: students draw two or three shape cards, arrange matching edges, then earn a point for naming the outline correctly.
Have students design a playground outline from three triangle or quadrilateral pieces, then label the polygon formed by the outside edge.
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Printable 3.MG.4.f Worksheet
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Related Standards
- 3.MG.4.c
Identify and describe triangles, quadrilaterals, pentagons, hexagons, and octagons in various orientations, with and without contexts.
- 3.MG.4.e
Classify and compare polygons (triangles, quadrilaterals, pentagons, hexagons, octagons).
- 3.MG.4.d
Identify and name examples of polygons (triangles, quadrilaterals, pentagons, hexagons, octagons) in the environment.
- 3.MG.4.g
Subdivide a three-sided or four-sided polygon into no more than three parts and name the resulting polygons.
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