Problem

Use the cosine function to find $A$ if $b=34 \mathrm{~m}$ and $c=41 \mathrm{~m}$ in the triangle $A B C$.
\[
A=\square^{\circ}
\]
(Round to the nearest tenth as needed.)

Answer

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Answer

So, the angle A in the triangle ABC is \(\boxed{34.0^{\circ}}\).

Steps

Step 1 :We are given that in triangle ABC, b = 34 m and c = 41 m. We are asked to find the angle A.

Step 2 :We can use the cosine rule to find the angle A. The cosine rule can be written as cos(A) = (b^2 + c^2 - a^2) / 2bc. However, we don't know the length of side a.

Step 3 :We can use the Pythagorean theorem to find the length of side a. The Pythagorean theorem states that a^2 = c^2 - b^2. Substituting the given values, we get a = \( \sqrt{41^2 - 34^2} = 22.9128784747792 \) m.

Step 4 :We can substitute the values of a, b, and c into the cosine rule to find A. So, A = arccos[(b^2 + c^2 - a^2) / 2bc] = arccos[(34^2 + 41^2 - 22.9128784747792^2) / (2 * 34 * 41)].

Step 5 :Calculating the above expression, we get A = 34.0 degrees.

Step 6 :Rounding to the nearest tenth as needed, we get A = 34.0 degrees.

Step 7 :So, the angle A in the triangle ABC is \(\boxed{34.0^{\circ}}\).

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