1. T2.3b Solving Right Triangles Bearing Problems II
3-8-19
T2.3b Solving Right Triangles Bearing Problems II
(Please get a handout from the front)
Easter Island: A land of secrets and mystery. But, more importantly, once paradise, now a tale of environmental disaster and harbinger of doom, if we do not heed the lesson…

2. Opener: Draw the triangle, determine the right angle, and answer the question.
The bearing from A to B is 32°
The bearing from B to C is 254°
The bearing from A to C is 344°
The distance from A to C is 780 m.
What is the distance from A to B? N
To find angle A: 360° – 344° = 16° and 16° + 32° = 48° N B
254°
42°
To find angle B: 254° – 180° = 74° and 74° – 32° = 42° C
32° N x
16°
32°
780
If 48° + 42° = 90°, Then Angle C = 90 °
48°
344°
It is 1165 m from A to B. A

3. Active Learning Assignment Questions?
Everyone should have a handout of the examples.

4. Add this to the back of your compass:N 0° 0°
90°
90° W E
90°
90° 0° 0° S

5. LESSON: The second kind of bearing problems starts with a north-south line and uses an acute angle to show the direction, either east or west from this line. Either N or S always comes first, followed by an acute angle and then E or W.
Examples:
N 42° E
N 52° W
S 31° E
S 40° W N N S S
40°
31°
42°
52°
If you prefer to change N 42° E to N E 42° that is fine. 5

6. The bearing from Fort A to Camp C is S 52° E, the bearing from Fort A to Base B is N 84° E, and the bearing from Base B to Camp C is S 38° W. A plane flying at 250 mph takes 2.4 hr to go from Fort A to Base B. Find the distance from Fort A to Camp C . Start by making a sketch. (Hint: D = r * t) (1 dec. pl.)
1. Can we find angle A?
3. What is angle C? N S N S
180° – 84° – 52° = 44°
44° + 46° = 90°
2. Can we find angle B?
4. How far is it from A to B?
84° – 38° = 46°
250 mi x 2.4 hr = 600 mi
600 mi B
84°
hr.
46° A
5. What are we looking for?
44°
38°
52°
6. Solve the problem. x C
The distance is miles. 6

7. An Alternate way of finding the answer:
1. Can we find angle A?
3. Can we find angle B?
180° – 84° – 52° = 44°
90° – 44° = 46° N S N S
2. What is angle C?
4. How far is it from A to B?
52° + 38° = 90°
250 x 2.4 = 600 mi
600 mi B
84°
5. What are we looking for?
46° A
44°
38° N S
6. Solve the problem.
52° x
52°
38° C
The distance is miles.

8. How can we find angle Sam?
Sam, Tigger, and Rusty live in three cities that form a triangle. The bearing from Sam’s to Tigger’s is N 37° 20’ E and they are 60 miles apart. The bearing from Sam’s to Rusty’s is S 52° 40’ E. Also, the bearing from Tigger’s to Rusty’s is S 22° 40’ W. How far is it from Sam’s to Rusty’s? (1 dec. pl.) N S
How can we find angle Sam?
Tigger x N S
37° 20’ + 52° 40’ = 90°
37° 20’
How can we find angle Tigger?
14° 40’
22° 40’
37° 20’ – 22° 40’ = 14° 40’
60 mi
Sam x
What are we looking for?
Solve the problem. x
52° 40’
x Rusty
It is 15.7 miles from Sam’s to Rusty’s.

9. Active Learning Assignment:
H/O 3: 23-25
(Answers)
#23. (156.2 mi.)
#24. (1.6 mi.)
#25. (123.5 mi.)
WOW: Successful people are successful because they take responsibility when things go wrong-they learn from it. People who do not take responsibility are not successful!