Grade 4 · Geometry

CCSS.MATH.CONTENT.4.G.A.2

Classify two-dimensional figures based on the presence or absence of parallel or perpendicular lines, or the presence or absence of angles of a specified size. Recognize right triangles as a category, and identify right triangles.

Read this standard on the official Common Core site

Lessons that teach this standard

• Parallel Lines, Perpendicular Lines and Symmetry

  How to sort flat figures by parallel sides, perpendicular sides and angle size, why a right triangle is its own category, and how to find every line of symmetry.