2D shapes are flat, plane shapes. Triangles have three sides and three angles that add up to 180°. Quadrilaterals have four sides and four angles that add up to 360°. Constructing triangles Learn how ...

Julia does a mirrors-on activity, sings a song, and uses examples to sort 2D figures. In this lesson, Julia does a mirrors-on activity, sings a song, and uses anchor charts and images of real-life ...

Two-dimensional (2D) shapes are completely flat. They cannot be picked up. A polygon is a 2D shape with straight sides that meet at vertices. Polygons have names that show the number of sides they ...

Researchers have developed a test that uses children's ability to assemble LEGO pieces to assess their spatial visualization ability. Spatial visualization is the ability to visualize 3D shapes in one ...