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What is the largest angle measure in a triangle with sides of lengths 3, 5, and 7? (I think you need to solve this with algebra)

 

Thank you!

 Dec 1, 2020
 #1
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Actually....we can use something called the Law of Cosines....the largest angle will be opposite the  greatest side

 

[If you haven't had trig....don't worry about it.....this solution will give you your answer ]

 

cos (angle)  =   [ 7^2 - 5^2  -3^2 ] / [ -2 (3) (5) ] 

 

cos (angle)  =  [ 15 ] / [- 30 ]

 

cos (angle)  = -1/2

 

arccos (-1/2)  =   angle =  120°

 

 

cool cool cool

 Dec 1, 2020

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