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In the diagram below, what are AC and BC?

Please don't round your answer (keep your answer as a square root) and solve with the Law of Sines/Cosines

In the diagram below, what are AC and BC? Please don't round your answer (keep your-example-1
User Kfx
by
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2 Answers

3 votes

Answer:

BC14.5 AC 11.3

Explanation:

User Robert Davis
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7.3k points
1 vote


\( BC \) is
\( (60)/(\sin 105^\circ) \) and
\( AC \) is
\( 30√(2) \).

To find the lengths of sides AC and BC in triangle ABC, we can use the Law of Sines.

The Law of Sines states:


\[ (\sin A)/(a) = (\sin B)/(b) = (\sin C)/(c) \]

In triangle ABC, given that
\(AB = 30\),
\( \angle BAC = 30^\circ\), and
\( \angle BCA = 45^\circ\), we can find side AC using the Law of Sines:


\[ (\sin \angle BAC)/(AB) = (\sin \angle BCA)/(AC) \]

Substitute the given values:


\[ (\sin 30^\circ)/(30) = (\sin 45^\circ)/(AC) \]

Now, solve for AC:


\[ AC = (30 \cdot \sin 45^\circ)/(\sin 30^\circ) \]


\[ AC = (30 \cdot (√(2))/(2))/((1)/(2)) \]


\[ AC = 30 \cdot √(2) \]

So,
\( AC = 30√(2) \).

Now, to find side BC, we can use the Law of Sines again:


\[ (\sin \angle ABC)/(AC) = (\sin \angle BCA)/(BC) \]


\[ (\sin (180^\circ - \angle BAC - \angle BCA))/(AC) = (\sin 45^\circ)/(BC) \]


\[ (\sin 105^\circ)/(30√(2)) = (√(2))/(BC) \]

Now, solve for BC:


\[ BC = (30√(2) \cdot √(2))/(\sin 105^\circ) \]


\[ BC = (60)/(\sin 105^\circ) \]

Using a calculator to find the exact value:


\[ BC \approx (60)/(\sin 105^\circ) \]

So,
\( BC \) is the reciprocal of the sine of
\( 105^\circ \):


\[ BC \approx (60)/(\sin 105^\circ) \]

Therefore,
\( BC \) is
\( (60)/(\sin 105^\circ) \) and
\( AC \) is
\( 30√(2) \).

User Jason Byrne
by
7.6k points