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# Bearings and direction word problems

- Intro Lesson5:56
- Lesson: 1a4:22
- Lesson: 1b2:21
- Lesson: 212:02
- Lesson: 34:27
- Lesson: 4a8:37
- Lesson: 4b0:41
- Lesson: 57:01
- Lesson: 69:05

### Bearings and direction word problems

#### Lessons

Theorems that are useful:

Pythagorean Theorem: $a^{2} + b^{2} = c^{2}$

Trig ratio: $\sin \theta = \frac{O}{H}$

$\cos \theta = \frac{A}{H}$

$\tan \theta = \frac{O}{A}$

Law of sine: $\frac{a}{\sin A} = \frac{b}{\sin B} = \frac{c}{\sin C}$

Law of cosine: $c^{2} = a^{2} + b^{2} - 2ab \cos C$

- Introduction
__Introduction to Bearings and Direction Word Problems__ - 1.
**Evaluate A Bearings Word Problem Using Trigonometric Ratios**Charlie leaves home for a bike ride, heading 040°T for 5km.

a)How far north or south is Charlie from its starting point?b)How far east or west is Charlie from its starting point? - 2.
**Solve A Bearings Word Problem Using the Law of Cosine**A camping group made a return journey from their base camp. From the camp, they first travelled 120°T for 3km. Then they travelled 210°T for 9km. Determine the direction and distance they need to travel if they want to return to the base camp now.

- 3.
**Analyze A Bearings Word Problem Using Trigonometric Ratios and the Law of Cosine**Melody and April go to the same school. Melody's home is 3.5km with a bearing of S16°W from school whilst April's home is 2.4km with a bearing of N42°E from school. How far away are their homes from each other?

- 4.
**Triangulate the Location of an Earthquake**Radar X detected an earthquake N55°E of it. 16km due east of Radar X, Radar Y detected the same earthquake N14°W of it.

a)Determine the earthquake from Radar X and Y.b)Which Radar is closer to the earthquake? - 5.
**Estimate the Height of an Object**A plane is sighted by Tom and Mary at bearings 028°T and 012°T respectively. If they are 2km away from each other, how high is the plane?

- 6.
**Applying Law of Sine and Law of Cosine**Consider the following diagram.

Find the distance between P and Q.