Rosamiran, Lean Grace R., <br/><br/>
Effectiveness of manipulative device in understanding trigonometric concepts / 
author. 
 - xiii, 186 leaves :  Colored illustrations, tables, figures ;  28 cm. 
<br/><br/>Includes bibliographical references. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Effectiveness.<br/>Manipulative device.<br/>Trigonometry.