Math Problem Statement

Find the unknown value x for the triangle with angles 55°, 47°, and the side opposite the 47° angle as 60 cm.

Solution

The question involves solving for the unknown side xx in the triangle using the Law of Sines. Let's extract the information and solve it step by step:

Given Information:

  1. Y=55\angle Y = 55^\circ
  2. Z=47\angle Z = 47^\circ
  3. Side YZ=60cmYZ = 60 \, \text{cm}.
  4. Unknown: xx, the length of side XYXY.

Steps to Solve:

Step 1: Find X\angle X

The sum of angles in a triangle is 180180^\circ.
X=180YZ=1805547=78.\angle X = 180^\circ - \angle Y - \angle Z = 180^\circ - 55^\circ - 47^\circ = 78^\circ.

Step 2: Apply the Law of Sines

The Law of Sines states: sinYx=sinZ60.\frac{\sin \angle Y}{x} = \frac{\sin \angle Z}{60}.

Rearranging for xx: x=60sinYsinZ.x = \frac{60 \cdot \sin \angle Y}{\sin \angle Z}.

Step 3: Calculate the Values

Using a scientific calculator:

  • sin550.8192\sin 55^\circ \approx 0.8192,
  • sin470.7314\sin 47^\circ \approx 0.7314.

Substitute these into the equation: x=600.81920.731449.1520.731467.2cm.x = \frac{60 \cdot 0.8192}{0.7314} \approx \frac{49.152}{0.7314} \approx 67.2 \, \text{cm}.

Final Answer:

The unknown side xx is approximately 67.2 cm.

Would you like further clarification on any step or need assistance with related problems? Here are some related questions you might explore:

  1. How do you calculate the area of a triangle using trigonometry?
  2. Can we solve this problem using the Law of Cosines instead of the Law of Sines?
  3. What is the significance of the Law of Sines in non-right triangles?
  4. How does the angle measurement affect side length in a triangle?
  5. How would you solve this if the angles were measured in radians?

Tip: Always ensure your calculator is set to the correct mode (degrees or radians) based on the problem's requirements.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Law of Sines
Sum of Angles in a Triangle

Formulas

Law of Sines: sin(A)/a = sin(B)/b
Sum of Angles in a Triangle: A + B + C = 180°

Theorems

Law of Sines

Suitable Grade Level

Grades 10-12