The Triangle Troubleshooter

The SinCosTan cards for finding out why a trig answer does not match the key, and fixing it

Worksheets are sorted by topic. A student with a wrong answer only knows the symptom: the key says 111.8 degrees and the calculator said 68.2, or the key lists two triangles and the work found one. The Triangle Troubleshooter is sorted by symptom. Eight cards cover radian mode, choosing the law, SOH CAH TOA labels, the no-triangle case, the second triangle in the ambiguous case, the obtuse angle arcsin cannot return, early rounding, and the second angle inverse trig leaves out. Each names the cause, shows the wrong answer beside the right one, and gives the fix. Three checks follow: a thirty-second answer check, work laid out for partial credit, and a routine for test day. The back has a mistake log, a which-law card and ten practice triangles with answers. For students of trigonometry, and teachers, who may print the pages for their own students. With your purchase comes a personalised sheet that solves your own triangle, every solution included.

Look inside

Two full pages from the workbook, exactly as printed. Click either to read it at full size before you decide.

What is in it

• Card 1: an answer wildly off (radian mode)
• Cards 2 and 3: which law, and SOH CAH TOA labels
• Cards 4 and 5: no triangle, and the second triangle
• Card 6: the obtuse angle arcsin cannot return
• Cards 7 and 8: early rounding, and the missing second angle
• Three checks: answers, partial credit, test day
• A mistake log and a which-law card
• Ten practice triangles with answers
• A personalised sheet: your triangle, every solution

The pack complements the free Law of Sines and Cosines Calculator. It solves a triangle; the cards find out why your own answer does not match the key.