## janessia 2 years ago Isaac is looking through binoculars on a whale watching trip when he notices a sea otter in the distance. If he is 20 feet above sea level in the boat, and the angle of depression is 30 degrees, how far away from the boat is the otter (to the nearest foot)?

1. mark_o.

hello are you there? do u think you can draw this first before you can solve?

2. mark_o.

@ janessia

3. janessia

hmm idk

4. janessia

how would i draw it?

5. mark_o.

do you know the angle of depression?

6. mark_o.

|dw:1351530728427:dw|

7. mark_o.

the height y=20 , the x= distance angle theta = angle of depression

8. janessia

so how do i solve this?

9. mark_o.

|dw:1351530990457:dw|

10. mark_o.

you can try tangent

11. janessia

opposite hypotenuse?

12. janessia

13. janessia

?

14. mark_o.

sorry my pc got frozen,,, yes try that tangent

15. mark_o.

let me know what you getting

16. mark_o.

$\tan \theta =\frac{ 20 }{ x } ,......$ then what is x=?

17. mark_o.

18. janessia

ohk but hmmmm??? im so confused

19. janessia

just forget it its fine

20. mark_o.

$\tan \theta =\frac{ 20 }{ x }$ so here we want x, therefore multiply both sides by x, to get $xtan \theta =\frac{ 20 }{ x }.x$ $x \tan \theta =20$ divide both sides by tan o gives $\frac{ x \tan \theta }{ \tan \theta }=\frac{ 20 }{ \tan \theta }$ w/c gives $x=\frac{ 20 }{ \tan \theta }....$ x=?

21. mark_o.

did you get it? angle of depression $\theta =30$

22. mark_o.

so x= 20/ tan 30 what did you get?