Patent ID: 7278217

Claim:
A trigonometric teaching aid for providing students with real life applications for the principles of trigonometry comprising: an elongated rectangular planar support member; a first protractor having a straight diametral base and a semicircular sector with an origin; a first adjustable fastener pivotally connecting said first protractor at said origin thereof to an upper end of said support member for rotation about a first transverse axis; a sight tube connected to and aligned with said base of said first protractor and having a longitudinal axis normal to said first transverse axis; a cross hair member attached at each end of said sight tube parallel to said first transverse axis; a level member carried with said sight tube and having means for indicating when said sight tube is horizontally positioned; scaling graduations on said semicircular sector of said first protractor to denote the angle of inclination of said sight tube relative to said support member; a second protractor having a straight diametral base and a semicircular sector with an origin; a second adjustable fastener pivotally connecting said second protractor at said origin thereof to a lower end of said support member for rotation about a second transverse axis; and scaling graduations on said semicircular sector of said second protractor to denote the angle of inclination of said sight tube relative to said support member whereby the angles of inclinations may be used in conjunction with trigonometric tables to determine physical measurements of objects being viewed.