Questions: Use the inverse of cosine to find the missing angle. Round your answer to the nearest tenth.
θ ≈
Transcript text: Use the inverse of cosine to find the missing angle. Round your answer to the nearest tenth.
(1 point)
$\theta \approx$ $\square$
Solution
Solution Steps
Step 1: Identify the given values
The problem provides the lengths of the adjacent side (9) and the hypotenuse (12) of a right triangle.
Step 2: Set up the inverse cosine function
To find the angle θ, use the inverse cosine function (cos⁻¹). The cosine of an angle in a right triangle is the ratio of the length of the adjacent side to the hypotenuse:
\[ \cos(\theta) = \frac{\text{adjacent}}{\text{hypotenuse}} = \frac{9}{12} \]
Step 3: Calculate the angle using a calculator
Use a calculator to find the inverse cosine of \(\frac{9}{12}\):
\[ \theta = \cos^{-1}\left(\frac{9}{12}\right) \approx \cos^{-1}(0.75) \]
Final Answer
Using a calculator, \(\theta \approx 41.4^\circ\).