# finding angles using bearings

• Feb 27th 2008, 04:10 PM
boonies
finding angles using bearings
A man starts walking from point A at a bearing of 56°. He walks for 400m and stops at point B. He then walks a bearing of 300° for 200m and stops at point C. From there he returns to point A.

Could I have some help finding the interior angles of this triangle, using theorems or trig or something, I am completely lost...
• Feb 27th 2008, 09:57 PM
earboth
Quote:

Originally Posted by boonies
A man starts walking from point A at a bearing of 56°. He walks for 400m and stops at point B. He then walks a bearing of 300° for 200m and stops at point C. From there he returns to point A.

Could I have some help finding the interior angles of this triangle, using theorems or trig or something, I am completely lost...

1. Make a sketch.

2. The greyed angle must be 56°. Then you can calculate the red angle.

3. Now use Cosine rule to calculate $\overline{AC}$

4. Now you can use either Sine rule or Cosine rule to calculate the missing angles.