Back to revision notes Open full-size SVG Print mind map M34 · Overview Trigonometry in general triangles mind map Use your browser’s Print command for A4 landscape, or choose A3 in its paper settings. The SVG remains sharp when enlarged. A text version follows the map.
Read the mind map as text Sine rule Pair labels: Higher: a opposite A; a/sinA = b/sinB = c/sinCLengths: Higher: A=30°,B=45°,a=6 → b=6√2 cmAmbiguity: Higher: Inverse sin may have supplementary solution; check sumCosine rule Length: Higher: a²=b²+c²−2bc cosA; included angle between b,cAngle: Higher: cosA=(b²+c²−a²)/(2bc); a opposite ARight angle: Higher: A=90° gives Pythagoras as special caseTriangle area Included angle: Higher: Area = ab sinC/2; 8,5,30° → 10 cm²Find angle: Higher: sinC=2 area/(ab); consider C and 180°−CApplications Bearings: Higher: Derive interior angles from north lines before ruleThree dimensions: Higher: Find useful lengths/angles first; degrees; avoid early roundingConnections Sine rule → Cosine rule: Known sides and angles determine the useful rule Cosine rule → Triangle area: Included angles control cosine-rule and area inputs 