Math Problem Statement

Use the Law of Sines to solve the triangle. Given: A = 37°, a = 9, b = 8. Find angles B, C, and side c. Round your answers to two decimal places.

Solution

Let's use the Law of Sines to solve the triangle. Here’s the given information:

  • Angle A=37A = 37^\circ
  • Side opposite AA (i.e., aa) = 9
  • Side opposite BB (i.e., bb) = 8

Step 1: Apply the Law of Sines

The Law of Sines states:
asinA=bsinB=csinC\frac{a}{\sin A} = \frac{b}{\sin B} = \frac{c}{\sin C}

We'll first find angle BB using: sinBb=sinAa\frac{\sin B}{b} = \frac{\sin A}{a}

Step 2: Solve for sinB\sin B

sinB=bsinAa=8sin379\sin B = \frac{b \cdot \sin A}{a} = \frac{8 \cdot \sin 37^\circ}{9}

Using sin370.6018\sin 37^\circ \approx 0.6018: sinB=80.601894.814490.535\sin B = \frac{8 \cdot 0.6018}{9} \approx \frac{4.8144}{9} \approx 0.535

Now, find BB: B=sin1(0.535)32.41B = \sin^{-1}(0.535) \approx 32.41^\circ

Step 3: Find Angle CC

Since the sum of the angles in a triangle is 180180^\circ: C=180AB=1803732.41110.59C = 180^\circ - A - B = 180^\circ - 37^\circ - 32.41^\circ \approx 110.59^\circ

Step 4: Find Side cc

Now, use the Law of Sines again to find side cc: csinC=asinA\frac{c}{\sin C} = \frac{a}{\sin A}

So: c=asinCsinA=9sin110.59sin37c = \frac{a \cdot \sin C}{\sin A} = \frac{9 \cdot \sin 110.59^\circ}{\sin 37^\circ}

Using sin110.590.9397\sin 110.59^\circ \approx 0.9397: c=90.93970.60188.45730.601814.05c = \frac{9 \cdot 0.9397}{0.6018} \approx \frac{8.4573}{0.6018} \approx 14.05

Final Answers

  • B32.41B \approx 32.41^\circ
  • C110.59C \approx 110.59^\circ
  • c14.05c \approx 14.05

Would you like me to clarify or elaborate on any step?


Here are five follow-up questions:

  1. How would the calculations change if angle AA was obtuse?
  2. How does the Law of Sines apply to non-right triangles?
  3. Can you solve a triangle if only two sides and no angles are known?
  4. What happens if sin1(x)\sin^{-1}(x) yields two possible angles?
  5. What are some real-world applications of the Law of Sines?

Tip: Always check if the triangle is ambiguous (SSA case) when using the Law of Sines.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Trigonometry
Law of Sines
Triangle

Formulas

Law of Sines: (a/sin(A)) = (b/sin(B)) = (c/sin(C))
Sum of angles in a triangle: A + B + C = 180°

Theorems

Law of Sines
Triangle Angle Sum Theorem

Suitable Grade Level

Grades 10-12