Lloyd's work to find the missing angle measure (to the nearest degree) is shown. What mistake did Lloyd make? 9 units Lloyd's work: = X COS = 1° COS ܙܩ ܩ ܙܩ 5 units X

Trigonometry (MindTap Course List)
8th Edition
ISBN:9781305652224
Author:Charles P. McKeague, Mark D. Turner
Publisher:Charles P. McKeague, Mark D. Turner
Chapter3: Radian Measure
Section3.4: Arc Length And Area Of A Sector
Problem 66PS
icon
Related questions
Question

Pic attached

### Finding the Missing Angle of a Right Triangle (Example Problem)

Lloyd's attempt to find the missing angle measure (to the nearest degree) is shown. Review his work and identify the mistake he made.

#### Lloyd's Work:
```
cos (5/9) = x
  cos (5/9) = 1°
```

#### Diagram:
We are given a right triangle where:
- The hypotenuse is 9 units.
- The adjacent side to the angle \( x \) is 5 units.

#### Analysis:
Lloyd is attempting to use the cosine function, which is defined as:
\[ \cos(\theta) = \frac{\text{adjacent}}{\text{hypotenuse}} \]

Given:
\[ \cos(x) = \frac{5}{9} \]

The correct method to find the angle \( x \) is to use the inverse cosine (arccos) function:
\[ x = \cos^{-1}\left(\frac{5}{9}\right) \]

#### Mistake Identified:
Lloyd did not actually use the inverse cosine function (cosine inverse or arccos). Instead, he incorrectly interpreted \( \cos (5/9) \) as an angle measure, which is not mathematically appropriate.

Moreover, cosine values must always be between -1 and 1, and thus the cosine of a ratio like 5/9 should not yield an angle directly.

#### Corrected Work:
Apply the inverse cosine to find the angle \( x \):
\[ x = \cos^{-1}\left(\frac{5}{9}\right) \]

Using a calculator:
\[ x \approx \cos^{-1}(0.5556) \approx 56 \text{ degrees} \]

#### Conclusion:
Lloyd's mistake was not applying the inverse cosine function to find the angle. The correct measure of angle \( x \) is approximately 56 degrees.
Transcribed Image Text:### Finding the Missing Angle of a Right Triangle (Example Problem) Lloyd's attempt to find the missing angle measure (to the nearest degree) is shown. Review his work and identify the mistake he made. #### Lloyd's Work: ``` cos (5/9) = x cos (5/9) = 1° ``` #### Diagram: We are given a right triangle where: - The hypotenuse is 9 units. - The adjacent side to the angle \( x \) is 5 units. #### Analysis: Lloyd is attempting to use the cosine function, which is defined as: \[ \cos(\theta) = \frac{\text{adjacent}}{\text{hypotenuse}} \] Given: \[ \cos(x) = \frac{5}{9} \] The correct method to find the angle \( x \) is to use the inverse cosine (arccos) function: \[ x = \cos^{-1}\left(\frac{5}{9}\right) \] #### Mistake Identified: Lloyd did not actually use the inverse cosine function (cosine inverse or arccos). Instead, he incorrectly interpreted \( \cos (5/9) \) as an angle measure, which is not mathematically appropriate. Moreover, cosine values must always be between -1 and 1, and thus the cosine of a ratio like 5/9 should not yield an angle directly. #### Corrected Work: Apply the inverse cosine to find the angle \( x \): \[ x = \cos^{-1}\left(\frac{5}{9}\right) \] Using a calculator: \[ x \approx \cos^{-1}(0.5556) \approx 56 \text{ degrees} \] #### Conclusion: Lloyd's mistake was not applying the inverse cosine function to find the angle. The correct measure of angle \( x \) is approximately 56 degrees.
Expert Solution
steps

Step by step

Solved in 2 steps

Blurred answer
Recommended textbooks for you
Trigonometry (MindTap Course List)
Trigonometry (MindTap Course List)
Trigonometry
ISBN:
9781305652224
Author:
Charles P. McKeague, Mark D. Turner
Publisher:
Cengage Learning
Mathematics For Machine Technology
Mathematics For Machine Technology
Advanced Math
ISBN:
9781337798310
Author:
Peterson, John.
Publisher:
Cengage Learning,
Algebra & Trigonometry with Analytic Geometry
Algebra & Trigonometry with Analytic Geometry
Algebra
ISBN:
9781133382119
Author:
Swokowski
Publisher:
Cengage