Math Problem Statement

Solve the triangle with given values: a = 23.07 cm, b = 10.75 cm, and A = 30.2°.

Solution

To solve this triangle, we have:

  • Side a=23.07a = 23.07 cm
  • Side b=10.75b = 10.75 cm
  • Angle A=30.2A = 30.2^\circ

We need to determine whether there are possible solutions using the Law of Sines:

asinA=bsinB\frac{a}{\sin A} = \frac{b}{\sin B}

Step 1: Calculate sinB\sin B

sinB=bsinAa=10.75sin30.223.07\sin B = \frac{b \cdot \sin A}{a} = \frac{10.75 \cdot \sin 30.2^\circ}{23.07}

Calculating sin30.20.502\sin 30.2^\circ \approx 0.502:

sinB=10.750.50223.070.234\sin B = \frac{10.75 \cdot 0.502}{23.07} \approx 0.234

Now, find BB using the inverse sine function:

B=sin1(0.234)13.5B = \sin^{-1}(0.234) \approx 13.5^\circ

Step 2: Check for possible solutions

Since sinB\sin B is positive and less than 1, there are two possible cases for angle BB:

  1. B13.5B \approx 13.5^\circ
  2. B=18013.5166.5B' = 180^\circ - 13.5^\circ \approx 166.5^\circ

Step 3: Calculate angle CC

For each case, find angle CC:

  1. If B=13.5B = 13.5^\circ, then: C=180AB=18030.213.5136.3C = 180^\circ - A - B = 180^\circ - 30.2^\circ - 13.5^\circ \approx 136.3^\circ

  2. If B=166.5B = 166.5^\circ, then: C=18030.2166.5=16.7C = 180^\circ - 30.2^\circ - 166.5^\circ = -16.7^\circ

The second case is not possible because angle CC cannot be negative.

Step 4: Calculate side cc

Using the Law of Sines:

csinC=asinA    c=asinCsinA\frac{c}{\sin C} = \frac{a}{\sin A} \implies c = \frac{a \cdot \sin C}{\sin A}

Substitute a=23.07a = 23.07, sinA=0.502\sin A = 0.502, and sinCsin136.30.732\sin C \approx \sin 136.3^\circ \approx 0.732:

c=23.070.7320.50233.63 cmc = \frac{23.07 \cdot 0.732}{0.502} \approx 33.63 \text{ cm}

Thus, there is only one possible solution for the triangle, making option B the correct choice.

Would you like further details or have any questions?

Related Questions:

  1. How is the Law of Sines derived and why is it useful?
  2. What are the conditions for a triangle to have two possible solutions?
  3. How can you verify the correctness of your solution using trigonometry?
  4. What is the ambiguous case of the Law of Sines?
  5. How would the solution change if angle AA was obtuse?

Tip:

When solving triangles using the Law of Sines, always check for the ambiguous case, especially if given two sides and a non-included angle (SSA condition).

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Law of Sines
Triangle Ambiguity

Formulas

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

Theorems

Law of Sines

Suitable Grade Level

High School (Grades 10-12)