Solve each problem. See Examples 1 and 2. Distance between Two Ships A ship leaves its home port and sails on a bearing of S 61°50'. Another ship leaves the same port at the same time and sails on a bearing of N 28°10'E. If the first ship sails at 24.0 mph and the second sails at 28.0 mph, find the distance between the two ships after 4 hr.
Table of contents
- 0. Review of College Algebra4h 45m
- 1. Measuring Angles40m
- 2. Trigonometric Functions on Right Triangles2h 5m
- 3. Unit Circle1h 19m
- 4. Graphing Trigonometric Functions1h 19m
- 5. Inverse Trigonometric Functions and Basic Trigonometric Equations1h 41m
- 6. Trigonometric Identities and More Equations2h 34m
- 7. Non-Right Triangles1h 38m
- 8. Vectors2h 25m
- 9. Polar Equations2h 5m
- 10. Parametric Equations1h 6m
- 11. Graphing Complex Numbers1h 7m
2. Trigonometric Functions on Right Triangles
Trigonometric Functions on Right Triangles
Problem 2.5.30
Textbook Question
Solve each problem. See Examples 1 and 2. Distance between Two Cities The bearing from Atlanta to Macon is S 27° E, and the bearing from Macon to Augusta is N 63° E. An automobile traveling at 62 mph needs 1¼ hr to go from Atlanta to Macon and 1¾ hr to go from Macon to Augusta. Find the distance from Atlanta to Augusta.
Verified step by step guidance1
Identify the distances traveled from Atlanta to Macon and from Macon to Augusta using the formula \(\text{distance} = \text{speed} \times \text{time}\). For Atlanta to Macon, calculate \(d_1 = 62 \times 1.25\), and for Macon to Augusta, calculate \(d_2 = 62 \times 1.75\).
Draw a diagram representing the positions of Atlanta, Macon, and Augusta, including the bearings. The bearing from Atlanta to Macon is \(S 27^\circ E\), which means starting from south, rotate 27 degrees towards east. The bearing from Macon to Augusta is \(N 63^\circ E\), starting from north, rotate 63 degrees towards east.
Determine the angle between the two paths (Atlanta to Macon and Macon to Augusta) at point Macon. Since the bearings are given relative to the cardinal directions, find the interior angle between the two directions by adding or subtracting the given angles appropriately.
Use the Law of Cosines to find the distance from Atlanta to Augusta. Label the triangle with sides \(d_1\), \(d_2\), and the unknown side \(d\), and the included angle \(\theta\) found in the previous step. The Law of Cosines formula is: \(d^2 = d_1^2 + d_2^2 - 2 d_1 d_2 \cos(\theta)\).
Solve for \(d\) by taking the square root of both sides: \(d = \sqrt{d_1^2 + d_2^2 - 2 d_1 d_2 \cos(\theta)}\). This will give the distance from Atlanta to Augusta.
Verified video answer for a similar problem:This video solution was recommended by our tutors as helpful for the problem above
Video duration:
3mPlay a video:
0 Comments
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Bearing and Direction in Navigation
Bearing is a way to describe direction using angles relative to the cardinal points (N, S, E, W). For example, S 27° E means starting from south and rotating 27° towards east. Understanding how to interpret and convert these bearings into angles for calculations is essential for solving navigation problems.
Recommended video:
Finding Direction of a Vector
Distance, Speed, and Time Relationship
The relationship between distance, speed, and time is given by the formula distance = speed × time. Knowing the speed and travel time allows calculation of the distance between two points, which is crucial for determining the lengths of segments in the problem.
Recommended video:
Example 1
Law of Cosines for Non-Right Triangles
The Law of Cosines relates the lengths of sides of any triangle to the cosine of one of its angles. It is used to find an unknown side when two sides and the included angle are known, which is necessary here to find the distance between Atlanta and Augusta given the bearings and distances.
Recommended video:
Intro to Law of Cosines
Related Videos
Related Practice
Textbook Question
895
views
