Kailee1423 one year ago I need help figuring out how to solve for x on certain triangles. I can solve it easily if it has two sides or two angles already stated, but I don't know what to do if it only has one angle and one side. I'll give a couple examples in the comments.

1. Kailee1423

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2. Kailee1423

X is the hypotenuse. I forgot to draw it.

4. Kailee1423

Which third angle?

the top one

6. Kailee1423

Can you show how you got it?

yeah

sum of all the angles of a triangle is 180 so your one angle is given 20 and the other one is 90 as it is a rt angled triangle so the other angle is -180 -(90+20)=70

9. Kailee1423

Oh ok. So would I use Pythagorean triples to solve for x?

yeah

but one side is x and the other is 19 but you need to have data of another side

12. Kailee1423

How do I do that? This is so confusing. Lol

probably the question is incorrect wait i'm checking

no the question is wrong you got to have two sides

15. Kailee1423

It can't be wrong. I got it from my homework. Lol

any other info

17. Kailee1423

Here are the choices: A. 55.6 B. 55.8 C. 6.7 D. 6.5

pls wait

nope there's surely some problem

20. Kailee1423

I just don't think there is cuz there's other problems like this one but this one looked the simplest so I posted it.

ok

22. Kailee1423

I think I found something in my book. If I mark the other unknown side as x, too, then I could do 2x squared = 19 squared and then find the square root

why will you mark the other side as x

did they tell you that they are equal

25. Kailee1423

Hmmm..... good point lol

did they tell you the area of the triangle

28. Kailee1423

No, that's all it said besides the fact that it's not drawn to scale.

29. Kailee1423

And to round to the nearest 10th

yeah theres something wrong wait i'm asking a frnd of mine

@saseal

32. anonymous

this has got to do with inverse sine function

33. Kailee1423

34. anonymous

$\sin^{-1} (\frac{ 19 }{ x } = 20^{o}$

hey i got it

its 55.8

37. anonymous

you can try the options since its mcq

yeah

will you explain it to her

40. anonymous

ok

41. Kailee1423

I still don't know exactly how to solve it... Lol sorry, this stuff is confusing to me.

wait @Kailee1423 he'll explain it to you

43. anonymous

you know $\sin = \frac{ Opposite }{ Hypotenuse }$

44. anonymous

its a ratio of opposite and hypotenuse

45. Kailee1423

Yeah, but how do you know which side is opposite?

46. anonymous

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47. anonymous

thats how you know

you got to consider the 20 degree angle

then your sin 20=19/x sin 20 value is 0.34 so x=19/0.34=55.8

hey @Kailee1423 did you understand what we said

51. Kailee1423

How did you get 0.34?

calculater sweety

just in a calculater try the value of sin 20

54. Kailee1423

Oh ok. Why is it the sin of 20 instead of 19?

55. anonymous

$\sin 20 = 19/x$$0.342=19/x$$0.342x=19$$19/0.342=x$

56. anonymous

the angle is 20

because we always finf sin of an angle and not of a side

58. anonymous

you dont sine the length only angle

yeah

now u understand

61. anonymous

its actually 55.6

62. Kailee1423

Thank you both! :) Sorry, my computer crashed.