What are classroom items have obtuse angles?

Classroom items that have obtuse angles include certain types of protractors, which are designed to measure angles greater than 90 degrees. Additionally, some desks and tables may have obtuse angles in their leg designs or corners. A triangular ruler can also feature obtuse angles, particularly in its design for drafting and geometry work. Lastly, certain shelving units or display boards may incorporate obtuse angles in their construction.