Texas Essential Knowledge and Skills (TEKS):
2.8.B

classify and sort three-dimensional solids, including spheres, cones, cylinders, rectangular prisms (including cubes as special rectangular prisms), and triangular prisms, based on attributes using formal geometric language;

Texas Essential Knowledge and Skills (TEKS):
2.8.C

classify and sort polygons with 12 or fewer sides according to attributes, including identifying the number of sides and number of vertices;

Texas Essential Knowledge and Skills (TEKS):
2.8.E

decompose two-dimensional shapes such as cutting out a square from a rectangle, dividing a shape in half, or partitioning a rectangle into identical triangles and identify the resulting geometric parts.

Florida - Benchmarks for Excellent Student Thinking:
MA.2.GR.1.1

Identify and draw two-dimensional figures based on their defining attributes. Figures are limited to triangles, rectangles, squares, pentagons, hexagons and octagons.

Florida - Benchmarks for Excellent Student Thinking:
MA.2.GR.1.2

Categorize two-dimensional figures based on the number and length of sides, number of vertices, whether they are closed or not and whether the edges are curved or straight.

2nd Grade Math - 2- & 3-Dimensional Figures Lesson

A two-dimensional figure is a figure without thickness; it is flat.

A polygon is a two-dimensional figure made up of non-overlapping, straight line segments.

The point where two line segments meet is a vertex.