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anonymous
 one year ago
In triangle ABC, a = 3, b = 5, and c = 7. Find the approximate value of angle A.
22°
38°
142°
158°
anonymous
 one year ago
In triangle ABC, a = 3, b = 5, and c = 7. Find the approximate value of angle A. 22° 38° 142° 158°

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johnweldon1993
 one year ago
Best ResponseYou've already chosen the best response.1We can use the law of cosine here we know \[\large a^2 = b^2 + c^2  2bc \times cos(A)\] So since we want to solve for A we need to rearrange this into \[\large A = \arccos(\frac{a^2  b^2  c^2}{2bc})\] So just plug in everything you have and solve

johnweldon1993
 one year ago
Best ResponseYou've already chosen the best response.1the inverse cosine function also known as \(\large cos^{1}\)

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0okay and i just got .92

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0btw i dont have an actual calculator

johnweldon1993
 one year ago
Best ResponseYou've already chosen the best response.1The 0.92 is what you get when you do everything in the parenthesis...now you just need the inverse cosine of that Which, since you dont have a calculator...comes out to 21.786

johnweldon1993
 one year ago
Best ResponseYou've already chosen the best response.1So that would lead to your "approximate" answer to be 22 degrees
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