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Ch. 7 - Applications of Trigonometry and Vectors
Lial - Trigonometry 12th Edition
Lial12th EditionTrigonometryISBN: 9780136552161당신이 사용하는 게 아니라요?교과서 변경
8장, 문제 20

Solve each triangle ABC.


B = 38° 40', a = 19.7 cm, C = 91° 40'

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First, convert the given angles from degrees and minutes to decimal degrees for easier calculation. For example, 38° 40' becomes \(38 + \frac{40}{60}\) degrees, and similarly for 91° 40'.
Next, find the measure of the third angle \(A\) in triangle \(ABC\) using the fact that the sum of angles in a triangle is 180°. So, calculate \(A = 180° - B - C\).
Use the Law of Sines to find the missing sides. The Law of Sines states: \(\frac{a}{\sin A} = \frac{b}{\sin B} = \frac{c}{\sin C}\). You already know side \(a\) and angles \(B\) and \(C\), and now angle \(A\).
Set up the ratio to find side \(b\): \(b = a \times \frac{\sin B}{\sin A}\). Calculate \(b\) using the known values.
Similarly, find side \(c\) using \(c = a \times \frac{\sin C}{\sin A}\). This will give you all sides and angles of triangle \(ABC\).

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주요 개념

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i & j Notation