Warm – Up

Law of Cosines Section 6.2

Objectives Students will be able to…  Find the area of an oblique triangle using the Law of Sines  Solve oblique triangles using the Law of Cosines  Solve application problems for all triangles using trigonometry

Homework Law of Cosines Worksheet - EVENS

Area of an Oblique Triangle (Proof) A B C a b c 0 h A B C a b c 0 h

Area of an Oblique Triangle (Formulas)

Example Find the area of a triangle with side lengths 90m and 52m and an included angle of 102°.

Practice On law of Sines worksheet, complete last 4 problems – finding the area of the given triangle ________ minutes; stop at ____________

Law Of Cosines – SSS and SAS

Example - SAS

Example – SSS Find the three angles given side a = 8 ft, b = 19 ft and c = 14 ft A B C a b c

Example The pitcher’s mound on a women’s softball field is 43 ft from home plate and the distance between the bases is 60 ft. (The pitcher’s mound is not halfway between home plate and second base.) How far is the pitcher’s mound from first base?

Practice Law of Cosines Worksheet

Closure 1) Given a = 11, b = 14 and c = 20, solve for the remaining angle and sides 2) Given A = 135°, b = 4 and c = 9