OCR GCSE Mathematics · J560
Specification 8.01f · Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Foundation), Paper 4 (Higher), Paper 5 (Higher), Paper 6 (Higher)
Revise: Geometric Construction ToolsTo measure an angle, put the protractor’s centre mark exactly on the vertex and line up its straight baseline with one arm. Begin at the 0° mark on that arm and follow that scale to the other arm. Many protractors have two scales running in opposite directions, so a quick estimate helps: an angle visibly wider than a right angle must measure more than 90°.