Appropriate year levels for the Plato’s protractor investigations
The Plato’s protractor investigations are aimed at students between years 9 and 12.
Moore’s (2013) teaching experiment built, in part, on an argument by David Bressoud (2010) that the teaching of triangle trigonometry earlier in secondary school than circle trigonometry has created a disconnect between measurement in degrees and in radians. Bressoud makes the point that trigonometry was originally defined in ancient times in terms of circle trigonometry. He argues that students at year nine should be introduced to both circle and triangle trigonometry. In Australia circle trigonometry does not appear in the curriculum until level 10 (ACMMG274). However, research in 1998 by Margaret Kendal and Kaye Stacey recommended that both methods be adopted from year nine in Australian schools. The lesson plan for Mathomat, Unwrapping the Circle by Susie Groves and Peter Grover (1998) introduced students to the use of radians in Mathomat for angle measure in a way that dealt with understanding angle as a quantity. This lesson plan, which can be downloaded at no charge from this website at the link below, is also aimed at years 9 to 12.