Geometry › Triangles by angle

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.

LTI launch URL (help)
https://schoolyourself.org/page/lti/sy/geometry/triangle-angles