Math Problem Statement

use law of sines and the ambiguous case

Solution

To solve for A\angle A in ABC\triangle ABC using the Law of Sines and considering the ambiguous case (SSA - Side-Side-Angle), we have:

  • B=75\angle B = 75^\circ
  • BC=31BC = 31 meters (side aa)
  • AC=6AC = 6 meters (side bb)

We want to find mAm\angle A.

Step-by-Step Solution Using Law of Sines and Ambiguous Case:

  1. Apply the Law of Sines:

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

Substitute the known values:

sinA31=sin756\frac{\sin A}{31} = \frac{\sin 75^\circ}{6}

  1. Calculate sin75\sin 75^\circ:

sin75=sin(9015)=cos15\sin 75^\circ = \sin(90^\circ - 15^\circ) = \cos 15^\circ

We know cos150.9659\cos 15^\circ \approx 0.9659 (from standard trigonometric values).

Thus:

sin750.9659\sin 75^\circ \approx 0.9659

  1. Solve for sinA\sin A:

sinA31=0.96596\frac{\sin A}{31} = \frac{0.9659}{6}

sinA=31×0.96596\sin A = 31 \times \frac{0.9659}{6}

sinA31×0.1609833\sin A \approx 31 \times 0.1609833

sinA4.9905\sin A \approx 4.9905

Recognizing the Ambiguous Case:

Here we encounter an issue because sinA>1\sin A > 1, which is not possible for a valid angle. Let's address this by acknowledging:

The ambiguous case involves two potential solutions or no valid solution when:

  • We have two sides and a non-included angle.
  • The sin\sin function can lead to multiple triangles under certain angle and side combinations.

In our scenario:

  1. Check for valid or invalid configurations:

Using the given:

sinBb=sin756\frac{\sin B}{b} = \frac{\sin 75^\circ}{6}

Already established correct initial calculation path.

Given angle:

  1. Confirm side condition alignment by valid approach-check.
  2. Interpret solution results based on valid calculation steps.

Direct next steps if correct detail base:

A=180(B+C)A = 180^\circ - (B + \angle C)

Thus review given facts again and solve accurately given setups!

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Law of Sines
Ambiguous Case

Formulas

Law of Sines: sin A / a = sin B / b

Theorems

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Suitable Grade Level

High School