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5 votes
Find degree of angle with 2 sides of 14 and 5

User GitGitBoom
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2 Answers

3 votes

answer:

To find the degree of an angle given two sides of a triangle, you can use the law of cosines. The formula is:


\[ c^2 = a^2 + b^2 - 2ab \cdot \cos(C) \]

Where
\(a\) and
\(b\) are the lengths of the sides of the triangle and
\(C\) is the angle opposite side \(c\).

Let's denote the sides as follows:


\(a = 14\) (one side)


\(b = 5\) (another side)


\(c\) would be the side opposite to the angle we're trying to find.

To find the angle
\(C\), we rearrange the law of cosines formula:


\[ \cos(C) = (a^2 + b^2 - c^2)/(2ab) \]

In this case, we're looking to find angle
\(C\) opposite to the side of length 14 and 5. Substituting the given values:


\[ \cos(C) = (14^2 + 5^2 - c^2)/(2 * 14 * 5) \]


\[ \cos(C) = (196 + 25 - c^2)/(140) \]

\
[ \cos(C) = (221 - c^2)/(140) \]

Now, let's solve for
\(c^2\):


\[ 221 - c^2 = 140 \cdot \cos(C) \]


\[ c^2 = 221 - 140 \cdot \cos(C) \]


\[ c^2 = 221 - 140 \cdot \cos(C) \]

To find the degree of angle
\(C\), take the inverse cosine (arccos) of the value obtained for
\(\cos(C)\):


\[ C = \arccos\left((221 - c^2)/(140)\right) \]

Please note that to compute the exact degree of angle
\(C\), we need to know the exact length of the third side
\(c\) or have further information about the triangle. If you have the value of the side
\(c\), you can substitute it into the equation to find the degree of angle
\(C\).

User Benjamin Schmidt
by
8.6k points
3 votes
5.6 is the right answer.
User Uranus
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8.2k points