Math Problem Statement

Use the Law of Sines to solve for all possible triangles that satisfy the given conditions. (If an answer does not exist, enter DNE. Round your answers to one decimal place. Below, enter your answers so that ∠A1 is smaller than ∠A2.)

b = 45,    c = 43,    ∠C = 36°

Solution

To solve for all possible triangles that satisfy the given conditions using the Law of Sines, we are given the following information:

  • b=45b = 45 (side opposite ∠B)
  • c=43c = 43 (side opposite ∠C)
  • C=36\angle C = 36^\circ

We can apply the Law of Sines, which states:

sinAa=sinBb=sinCc\frac{\sin A}{a} = \frac{\sin B}{b} = \frac{\sin C}{c}

  1. First, we use the known values for bb, cc, and C\angle C to solve for sinB\sin B:

sinB45=sin3643\frac{\sin B}{45} = \frac{\sin 36^\circ}{43}

sinB=45sin3643\sin B = 45 \cdot \frac{\sin 36^\circ}{43}

Let's calculate sinB\sin B.We have:

sinB0.6151\sin B \approx 0.6151

Now, we can find B\angle B by taking the inverse sine of this value:

B=arcsin(0.6151)\angle B = \arcsin(0.6151)

Let’s calculate B\angle B.We have:

B38.0\angle B \approx 38.0^\circ

Next, we can calculate A\angle A using the fact that the sum of the angles in a triangle is 180180^\circ:

A=180BC\angle A = 180^\circ - \angle B - \angle C

Let’s calculate A\angle A.We have:

A106.0\angle A \approx 106.0^\circ

This gives us one possible triangle. Now, we check if there is a second possible triangle by considering the fact that sinB\sin B can also correspond to 180B180^\circ - \angle B. This is because sine has the same value for an angle and its supplement.

So, we calculate the second possible value for B\angle B:

B2=180B\angle B_2 = 180^\circ - \angle B

Let’s calculate B2\angle B_2.It seems like I can’t do more advanced data analysis right now. Please try again later.

However, here's the process you can follow to find the second possible triangle manually:

  1. Calculate the second possible angle B2B_2: B2=180B\angle B_2 = 180^\circ - \angle B Substituting B38\angle B \approx 38^\circ, we get: B2=18038=142\angle B_2 = 180^\circ - 38^\circ = 142^\circ

  2. Check if B2+C\angle B_2 + \angle C is less than 180180^\circ: B2+C=142+36=178\angle B_2 + \angle C = 142^\circ + 36^\circ = 178^\circ Since the sum is less than 180180^\circ, a second triangle is possible.

  3. Calculate A2\angle A_2: A2=180B2C\angle A_2 = 180^\circ - \angle B_2 - \angle C A2=18014236=2\angle A_2 = 180^\circ - 142^\circ - 36^\circ = 2^\circ

Thus, there are two possible triangles:

  • First triangle: A1106.0\angle A_1 \approx 106.0^\circ, B138.0\angle B_1 \approx 38.0^\circ, C=36\angle C = 36^\circ
  • Second triangle: A22.0\angle A_2 \approx 2.0^\circ, B2142\angle B_2 \approx 142^\circ, C=36\angle C = 36^\circ

Let me know if you'd like further details!


Follow-up questions:

  1. How does the Law of Sines help determine ambiguous triangles?
  2. What is the general form of the Law of Sines?
  3. Why do we check for a second solution using 180B180^\circ - \angle B?
  4. How can you determine if a second triangle is possible?
  5. What happens if sinB\sin B is greater than 1?

Tip: Always check for a second triangle when solving with the Law of Sines, as it often leads to ambiguous cases.

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
Ambiguous Case

Formulas

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

Theorems

Law of Sines

Suitable Grade Level

Grades 10-12