SOLUTION: Consider ABC with the measure of angle B equal to 60 degrees, and side lengths a=4 and c=5. What is an expression that is equivalent to the length of side b?

Algebra ->  Triangles -> SOLUTION: Consider ABC with the measure of angle B equal to 60 degrees, and side lengths a=4 and c=5. What is an expression that is equivalent to the length of side b?      Log On


   

Question 1114327: Consider ABC with the measure of angle B equal to 60 degrees, and side lengths a=4 and c=5. What is an expression that is equivalent to the length of side b?
Found 2 solutions by Alan3354, josgarithmetic:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Consider ABC with the measure of angle B equal to 60 degrees, and side lengths a=4 and c=5. What is an expression that is equivalent to the length of side b?
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See the Cosine Law.

Answer by josgarithmetic(39631) About Me  (Show Source):
You can put this solution on YOUR website!
a%5E2%2Bc%5E2-2%2Aa%2Ac%2Acos%28B%29=b%5E2
b=sqrt%28a%5E2%2Bc%5E2-2ac%2Acos%28B%29%29
b=sqrt%284%5E2%2B5%5E2-2%2A4%2A5%2Acos%2860%29%29
simplify. Compute b.