Curriculum placement
Grade 2. This describes the skill, not a learner estimate.
Sides, angles, and faces
Identify polygons and solids by sides angles and faces
Problem types
- Name a polygon
- Find a number of angles
- Faces, edges and vertices
- The flat face at the bottom of a solid
- Select the shapes with the same number of sides
- Select the drawn solids with a property
- Which two figures match exactly?
- Name the pieces of a cut figure
- Choose the solids with a property
Builds on
- Defining attributes of shapes
- Composing shapes · Earlier idea
A shape built from smaller shapes is itself a polygon whose sides and angles can be counted and named.
Leads to
- Classifying quadrilaterals
- Measuring angles
- Categories and subcategories of shapes · Extend the idea
Counting the sides of a polygon to name it grows into sorting triangles by how many of their sides are equal, the first step toward categories that sit inside one another.
- Cross-sections of solids · See it applied
A cross-section of a solid is a polygon, named by its sides and angles.
- Congruence criteria for triangles · Extend the idea
Telling congruent figures from near copies by their sides and corners is the informal idea that congruence criteria later make exact for triangles.
- Precise definitions in geometry · Extend the idea
Counting the sides and angles of a polygon becomes defining it precisely by what it must contain.
Related skills
- Shapes made by putting shapes together · Shared foundations
- Parallel lines, perpendicular lines, and symmetry · Shared foundations
Open the interactive map to explore lessons and skill connections.