Standard Alignments:

TEKS Math: 4.6.C

(C) Apply knowledge of right angles to identify acute, right, and obtuse triangles

AU Math: ACMMG165

(Y7) Classify triangles according to their side and angle properties and describe quadrilaterals (ACMMG165)

CCSS Math: 4.G.2

4.G.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.