## anonymous one year ago What is the length of side BD? ***Diagram attached below***

1. anonymous

2. anonymous

We can use trig ratios, do you know them?

3. anonymous

|dw:1441221685739:dw| we can just work with the pink triangle here

4. anonymous

$\sin \theta = \frac{ opp }{ hyp }~~~~\tan \theta = \frac{ opp }{ adj }~~~~\cos \theta = \frac{ adj }{ hyp }$ these are your trig ratios, which one can we apply here? |dw:1441221868984:dw|

5. anonymous

cosine?

6. anonymous

Yes! Now can you set it up?

7. anonymous

8. anonymous

$\cos 40°=\frac{ adjacent }{ hypotenuse }=\frac{ 20 }{ x }$

9. anonymous

Exactly!

10. anonymous

Okay thank you so much! I'll try to solve it now!

11. anonymous

Yw :) have fun!