NOTES Law of Cosines
Who's Law Is It, Anyway? Murphy's Law: Cole's Law ?? Anything that can possibly go wrong, will go wrong (at the worst possible moment). Cole's Law ?? Finely chopped cabbage
Solving an SAS Triangle The Law of Sines was good for ASA - two angles and the included side AAS - two angles and any side SSA - two sides and an opposite angle (being aware of possible ambiguity) Why would the Law of Sines not work for an SAS triangle? 15 No side opposite from any angle to get the ratio 26° 12.5
Law of Cosines
Applying the Cosine Law Now use it to solve the triangle we started with Label sides and angles Side c first C 15 26° 12.5 A B c
Applying the Cosine Law Now calculate the angles use and solve for B C 15 26° 12.5 A B c = 6.65
Applying the Cosine Law The remaining angle determined by subtraction 180 – 93.75 – 26 = 60.25 C 15 26° 12.5 A B c = 6.65 Experiment with Cosine Law Spreadsheet