Determine the area of a triangle with [tex]m \angle A = 27.8^{\circ}[/tex], [tex]m \angle B = 107.3^{\circ}[/tex], and [tex]c = 4[/tex].

A. area [tex]\approx 8 \text{ units }^2[/tex]
B. area [tex]\approx 10 \text{ units }^2[/tex]
C. area [tex]\approx 5 \text{ units }^2[/tex]
D. area [tex]\approx 15 \text{ units }^2[/tex]

Please select the best answer from the choices provided:
A
B
C
D



Answer :

To determine the area of the triangle with the given information, we start with the following given data:
- [tex]\( A = 27.8^\circ \)[/tex]
- [tex]\( B = 107.3^\circ \)[/tex]
- [tex]\( c = 4 \)[/tex] units.

Step 1: Calculate angle [tex]\( C \)[/tex]

The sum of all angles in a triangle is [tex]\( 180^\circ \)[/tex]. Therefore, we can find angle [tex]\( C \)[/tex]:
[tex]\[ C = 180^\circ - A - B = 180^\circ - 27.8^\circ - 107.3^\circ = 44.9^\circ. \][/tex]

Step 2: Use the Law of Sines to find the area

The formula for the area of a triangle using the Law of Sines is:
[tex]\[ \text{Area} = \frac{1}{2} \cdot c^2 \cdot \frac{\sin(A) \cdot \sin(B)}{\sin(C)} \][/tex]

First, we convert angles [tex]\( A \)[/tex], [tex]\( B \)[/tex], and [tex]\( C \)[/tex] from degrees to radians because trigonometric functions in most calculators and mathematical functions use radians:
[tex]\[ \sin(A) = \sin(27.8^\circ) \approx \sin(0.485) \approx 0.466 \][/tex]
[tex]\[ \sin(B) = \sin(107.3^\circ) \approx \sin(1.873) \approx 0.955 \][/tex]
[tex]\[ \sin(C) = \sin(44.9^\circ) \approx \sin(0.783) \approx 0.703 \][/tex]

Substitute these sin values and side [tex]\( c = 4 \)[/tex] into the area formula:
[tex]\[ \text{Area} = \frac{1}{2} \cdot 4^2 \cdot \frac{0.466 \cdot 0.955}{0.703} \][/tex]
[tex]\[ \text{Area} = \frac{1}{2} \cdot 16 \cdot \frac{0.44573}{0.703} \][/tex]
[tex]\[ \text{Area} = 8 \cdot \frac{0.44573}{0.703} \][/tex]
[tex]\[ \text{Area} \approx 8 \cdot 0.634 \][/tex]
[tex]\[ \text{Area} \approx 5.072 \][/tex]

Step 3: Compare with provided choices

The closest answer choice to our calculated approximate area (5.072) is:
[tex]\[ \approx 5 \text{ units}^2 \][/tex]

Therefore, the best answer from the choices provided is:
[tex]\[ \text{c. area} \approx 5 \text{ units}^2 \][/tex]