This lesson is a remix from Illustrative Mathematics.  It focuses on right triangles.  It can include acute and obtuse triangles in the lesson.  Extensions of the lesson allow students to combine triangles to make other polygons.https://goopenva.org/courses/4-g-are-these-right

This resource asks students to determine where a third point could be to create a right triangle, an obtuse triangle, and an acute triangle.