Rosamiran, Lean Grace R., Effectiveness of manipulative device in understanding trigonometric concepts / author. - Iriga City: University of Saint Anthony 2025 - xiii, 186 leaves: Colored illustrations, tables, figures ; 28 cm. Includes bibliographical references. Subjects--Topical Terms: Effectiveness.Manipulative device.Trigonometry. Dewey Class. No.: 516.24 / R788e