## anonymous one year ago The length of the shadow of a building is 100 meters, as shown below: The shadow of a building is 100 meters long. The acute angle that the shadow makes with the line joining the tip of the building to the end of the shadow measures 45 degrees. What is the height of the building?

1. anonymous

2. anonymous

@dan815 @jim_thompson5910 @zzr0ck3r @HS_CA

3. jim_thompson5910

how far did you get?

4. anonymous

not far

5. jim_thompson5910

do you have an equation set up?

6. anonymous

thats my problem

7. jim_thompson5910

|dw:1441154654870:dw|

8. jim_thompson5910

with respect to the 45 degree angle, we can add these labels |dw:1441154698897:dw|

9. jim_thompson5910

which trig function will we use?

10. anonymous

tangent

11. jim_thompson5910

12. jim_thompson5910

so tan(45) = h/100

13. jim_thompson5910

are you able to isolate h in `tan(45) = h/100` ?

14. anonymous

no clue

15. jim_thompson5910

it might help to evaluate tan(45) first use this calculator http://web2.0calc.com/ to find the value of `tan(45)` and tell me what that is

16. anonymous

1

17. jim_thompson5910

yep

18. jim_thompson5910

so `tan(45) = h/100` is the same as `1 = h/100`

19. jim_thompson5910

so h = ??

20. anonymous

100

21. jim_thompson5910

good

22. jim_thompson5910

this is a 45-45-90 triangle with congruent legs

23. anonymous

wait is that it? 100 is the answer?

24. anonymous

thanks :D

25. jim_thompson5910

yeah you multiply both sides of `1 = h/100` by 100 to isolate h, you'll find that h = 100