## kennedav000 Group Title So, on my right triangle triangle I have here, they give all the sides and are asking for an angle The sides are Opp=15 Adj=8 Hyp=17 And we are looking for the x angle. one year ago one year ago

1. geoffb Group Title

Do you know SOHCAHTOA? Your sine, cosine, and tangent laws?

2. kennedav000 Group Title

Yes

3. geoffb Group Title

Okay, since you know all three side lengths, you can use any of the three functions to determine x.

4. geoffb Group Title

For example, $$\sin x = \frac{\text{opp}}{\text{hyp}}$$

5. kennedav000 Group Title

And that is it? Just use 17 over 15 ,divide and my answer would be 1.13?

6. geoffb Group Title

It's not x = 1.13. It's sin x = 1.13.

7. kennedav000 Group Title

Ah, sorry for not using correct mathematical vocabulary.

8. geoffb Group Title

No, that's not my point. The point is, you need to solve for x. Right now, you only know sin x.

9. geoffb Group Title

You need to get rid of the sin.

10. kennedav000 Group Title

Oh? How is this done?

11. geoffb Group Title

One thing first. It's not 17/15, it's 15/17.

12. kennedav000 Group Title

Got it

13. geoffb Group Title

So, $$\sin x = \frac{15}{17} = 0.882$$

14. geoffb Group Title

To get rid of the sin, you calculate $$\sin^{-1}$$. On your calculator, you should have a way to do this.

15. geoffb Group Title

So, $$x = \sin^{-1} (\frac{15}{17})$$

16. kennedav000 Group Title

I did not know there was such an option? Thank you.

17. geoffb Group Title

You might need to hit something like 2nd function, or inverse, then hit sin.

18. geoffb Group Title

You should end up with something around 60 degrees, if it's sine of 15/17.

19. kennedav000 Group Title

This isn't my outcome, I get a decimal of 1.001

20. geoffb Group Title

Okay, so you took your amount (0.882) and hit inverse sine (sin^-1) and got 1.001?

21. kennedav000 Group Title

Oh but wait, that is sin(h), Sorry, personal mistake.

22. geoffb Group Title

No worries.

23. geoffb Group Title

Since you knew all the sides, you could have also done $$x = \cos^{-1} (\frac{8}{17})$$ or $$x = \tan^{-1} (\frac{15}{8})$$, and gotten identical answers.

24. kennedav000 Group Title

Odd, I get the decimal of 0.795, how does this lead to 60 degrees?

25. geoffb Group Title

What calculation gives you 0.795?

26. kennedav000 Group Title

Well, seeing as I'm using the computer based calculator, this may have swayed my calculation. When typed in, it shows up as *asinh(15 /17)*

27. geoffb Group Title

Where did you type that in?

28. kennedav000 Group Title

But lo, I have found my answer as you have predicted, thank you so much kind sir, It was simply a typing error.

29. geoffb Group Title
30. geoffb Group Title

Good stuff! You're very welcome. :)

31. kennedav000 Group Title

I shall be on my way! Good day to you, and thank you for your time.

32. geoffb Group Title

You too, David! Cheers!