## anonymous one year ago Pre-calculus: At a certain time of day, a 15-meter mast casts a 20 meter shadow. What is the angle of elevation of the sun?

1. Nnesha

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2. Nnesha

use the trig ratio to find x $\rm sin \rm \theta = \frac{ opposite }{ hypotenuse }~~~~ \cos \theta = \frac{ adjacent }{ hypotenuse } ~~\tan \theta = \frac{ opposite }{ adjacent }$

3. anonymous

@Nnesha So I'm doing tan because I know that the opposite is 15, and the adjacent is 20? And that's my answer? 15/20?

4. Nnesha

yes right then use the calculator to find the exact value

5. anonymous

I got .75, is that correct? @Nnesha

6. Nnesha

remember you should inverse tan $\huge\rm tan( x) =\frac{ 15 }{ 20 }$ $x= \tan^{-1} \frac{ 15 }{ 20 }$

7. Nnesha

find*

8. anonymous

@Nnesha So the cotangent....? Sorry I just started pre-calc last week so I'm not sure how to do that.

9. Nnesha

tan and cot are reciprocal not inverse use the calculator to find inverse tan

10. anonymous

@Nnesha So tan(15/20) in the calculator?

11. Nnesha

not tan inverse tan which calculator are u using google or ti84 ?

12. anonymous

@Nnesha Oh I figured it out! The final answer is 36.9. Do you mind explaining why I have to find the inverse?

13. Nnesha

yes that's right tan and invs are opposite like when you have to find side then you should apply tan and when you have to find an angle  then you should use invs tan

14. Nnesha

i found this from mathisfun website http://prntscr.com/8e6m50

15. Nnesha
16. anonymous

@Nnesha Thank you SO much. Your help was amazing!

17. Nnesha

np glad it helped goood work btw! keep it up!