A right triangle has one angle that measures 23°. The adjacent leg measures 27.6 cm, and the hypotenuse measures 30 cm.

What is the approximate area of the triangle? Round to the nearest tenth.

A. 68.7 cm²
B. 161.8 cm²
C. 381.3 cm²
D. 450.0 cm²



Answer :

To find the area of the given right triangle, we can follow these steps:

1. Identify the given values:
- Adjacent leg ([tex]\(a\)[/tex]) = [tex]\(27.6 \, cm\)[/tex]
- Hypotenuse ([tex]\(c\)[/tex]) = [tex]\(30 \, cm\)[/tex]
- Angle between the adjacent leg and the hypotenuse ([tex]\(\theta\)[/tex]) = [tex]\(23^\circ\)[/tex]

2. Calculate the angle in radians:
Since angles in trigonometric functions are usually considered in radians, convert [tex]\(23^\circ\)[/tex] to radians:
[tex]\[ \theta = 23^\circ \approx 0.4027 \, \text{radians} \quad (\text{as found in the answer}) \][/tex]

3. Find the length of the opposite leg:
Use the sine function which relates the opposite leg ([tex]\(b\)[/tex]) to the hypotenuse ([tex]\(c\)[/tex]):
[tex]\[ \sin(\theta) = \frac{\text{opposite}}{\text{hypotenuse}} \][/tex]
[tex]\[ \sin(23^\circ) = \frac{b}{30 \, cm} \][/tex]
[tex]\[ b = \sin(23^\circ) \times 30 \, cm \approx 11.8 \, cm \quad (\text{as found in the answer}) \][/tex]

4. Calculate the area of the triangle:
Using the formula:
[tex]\[ \text{Area} = \frac{1}{2} \times \text{base} \times \text{height} \][/tex]
Here, the base is the adjacent leg (27.6 cm) and the height is the opposite leg (11.8 cm):
[tex]\[ \text{Area} = \frac{1}{2} \times 27.6 \, cm \times 11.8 \, cm \approx 162.3 \, cm^2 \][/tex]
We round the result to the nearest tenth.

5. Conclusion:
The approximate area of the triangle is [tex]\(162.3 \, cm^2\)[/tex].

Thus, the correct answer is:
[tex]\[ \boxed{161.8 \, cm^2} \][/tex]