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26 votes
26 votes
Does someone knows how to do this one?

Does someone knows how to do this one?-example-1
User Kirill Fuchs
by
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1 Answer

14 votes
14 votes

Answer:

c) BC/tan(20°)

Explanation:

The mnemonic SOH CAH TOA can help you remember the relations between trig functions and angles. It tells you ...

Sin = Opposite/Hypotenuse

Cos = Adjacent/Hypotenuse

Tan = Opposite/Adjacent

In the case of the present triangle, these relations mean ...

sin(B) = AC/BC ⇒ AC = BCsin(70°)

cos(C) = AC/BC ⇒ AC = BCcos(20°)

tan(B) = AC/BA ⇒ AC = BAtan(70°)

tan(C) = BA/AC ⇒ AC = BA/tan(20°)

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The answer choice that is not on this list is ...

c) BC/tan(20°) . . . . . . not equivalent to AC

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Additional comment

The interior angle at C is the supplement of the given angle 160°. These angles form a linear pair.

C = 180° -160° = 20°

The interior angle at B is the complement of the interior angle at C.

B = 90° -20° = 70°

User Landon G
by
3.2k points