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In triangle ABC, we have AB = 5, BC = 8, and AC = 7.
Calculate cos(A), cos(B), and cos(C). 

 

I feel like the way to go is to drop an altitude, but I'm a bit confused after that. 

 Feb 24, 2022

Best Answer 

 #1
avatar+36417 
+1

Use cos law

 

c^2 = a^2 + b^2 - 2ab cos c

 

example   to find cos a

  8^2 = 5^2 + 7^2  - 2 ( 5 )( 7) cos a         solve for cos a       the others are similar

 Feb 24, 2022
 #1
avatar+36417 
+1
Best Answer

Use cos law

 

c^2 = a^2 + b^2 - 2ab cos c

 

example   to find cos a

  8^2 = 5^2 + 7^2  - 2 ( 5 )( 7) cos a         solve for cos a       the others are similar

ElectricPavlov Feb 24, 2022

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