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In △ABC,a=11 , b=20 , and c=28 . Find m∠A .
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In △ABC,a=11 , b=20 , and c=28 . Find m∠A .

User Rits
by
6.7k points

2 Answers

4 votes

Answer:18.4

Explanation:

User Richard Medeiros
by
6.4k points
4 votes

Answer:

18.4°

Explanation:

Use law of cosine.

a² = b² + c² − 2bc cos A

11² = 20² + 28² − 2(20)(28) cos A

121 = 1184 − 1120 cos A

cos A = 0.949

A = 18.4°

User Marcin Olichwirowicz
by
5.9k points
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