Math /7.2 – The Law of Sines 1
Q: We know how to solve right triangles using trig, but how can we use trig to solve any triangle? A: The Law of Sines (7.1/7.2) and The Law of Cosines (7.3). 2
Q: We know how to solve right triangles using trig, but how can we use trig to solve any triangle? A: The Law of Sines (7.1/7.2) and The Law of Cosines (7.3). 3
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To solve a triangle, we’ve needed to know some of its sides and angles. We can classify the possibilities like this (A = Angle, S = Side): Case 1: ASA or SAA 7
Case 2: SSA 8
Case 3: SAS 9
Case 4: SSS 10
Note: The Law of Sines helps us solve cases 1 and 2. The Law of Cosines helps us solve cases 3 and 4. 11
12 Pain in the SSA
13 Pain in the SSA
14 Pain in the SSA
15 Pain in the SSA
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22 Area of a Triangle (SAS)
23 Area of a Triangle (SAS)
24 Area of a Triangle (SAS)
25 Area of a Triangle (SAS)
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Let’s go back and prove the Law of Sines as well… 31
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