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## anonymous one year ago In ∆ABC, what is the value of cos B? a) 5/4 b) 3/4 c) 3/5 d) 4/5 e) 4/3

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1. anonymous

2. anonymous

do you know what ratio the cosine function represents?

3. anonymous

I forgot what it was... tbh.... I'm really horrible at math... and i couldn't catch on to it...

4. anonymous

Don't worry :) I can help you. Have you heard of SOH CAH TOA before?

5. anonymous

no i havent, my teacher never taught me that

6. anonymous

It essentially means $\sin=O/H, \cos=A/H, \tan=O/A$

7. anonymous

it's a mnemonic worth remembering for trigonometry.

8. anonymous

oohhh

9. anonymous

so if cos = adjacent/hypotenuse, do you know which to sides these are in relation to angle b?

10. anonymous

adjacent and hypotenuse?

11. anonymous

@Sepeario

12. anonymous

yes but which sides are they in the above triangle?

13. anonymous

3 and 5??

14. anonymous

right?

15. anonymous

@Sepeario

16. anonymous

yep, so the final ratio is?

17. anonymous

wait how would i put that in my calculator?

18. anonymous

i'm so sorry i literally forget so much stuff it's a problem....

19. anonymous

@Sepeario

20. anonymous

you can't really put that into a calculator. so what is the final answer?

21. anonymous

if adjacent = 3 and hypotenuse = 5 and cos 60 = a/h = ?

22. anonymous

frig..... um....

23. anonymous

it's 3/5??

24. anonymous

sorry i'm so tired and i have 6 online geometry tests to do by 1:18 p.m and its 8:21 a.m

25. anonymous

so is it 3/5 @Sepeario

26. anonymous

yep that's right

27. anonymous

good luck! and i'm sure you'll do well.

28. anonymous

i suck at math

29. anonymous

i'm gonna fail and have to repeat freshman year

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