Question

Help? Trigonometry and failing!

Use ΔDEF, shown below, to answer the question that follows:

Triangle DEF where angle E is a right angle. DE measures x. DF measures 55. Angle D measures 49 degrees.

What is the value of x rounded to the nearest hundredth? (image coming in a second!)

Answer 1

So you have an angle and a side and you have to find x so your going to have to use a trig ratio either sin cos tan

Answer 2

gotcha :)

Answer 3

What is the 55 in the problem?

Answer 4

adjacent opposite or hypotenuse?

Answer 5

adjacent hypotenuse I think - cos

Answer 6

55 is the hypotenuse

Answer 7

yes so what is your ratio?

Answer 8

this is where I get stuck ;-; so if it's cos it would be adjacent/hypotenuse

Answer 9

yep whats your angle in this problem?

Answer 10

so x/55, but what do I do about that? D:

Answer 11

49 is the angle

Answer 12

OH DUH

Answer 13

49/55 you're saying?

Answer 14

yes so you have to put that in the x after cos so cos(49)=x/55

Answer 15

the angle always goes with the sin cos or tangent and than the other part will always be the sides that your are dealing with

Answer 16

gotcha :)

Answer 17

now do you know what to do?

Answer 18

when I did cos(49), I got 0.656059028991

Answer 19

I hope that's right!

Answer 20

no

Answer 21

you have to solve for x

Answer 22

so when you do this you have to bring that 55 to the other side so x= an answer

Answer 23

sorry, I'm really new to this!

Answer 24

thats okay it takes time!

Answer 25

so you're saying x has to equal 55 for the time being? o.o

Answer 26

kinda you have to move 55 to the other side

Answer 27

with the cos(49)

Answer 28

alright, so cos(49) = 55/55 or 1?

Answer 29

no

Answer 30

so you have x/55 what could you do to get x by itself

Answer 31

divide both sides by 55?

Answer 32

close

Answer 33

multiply?

Answer 34

since its on the bottom you have to multiply

Answer 35

got it ^^

Answer 36

cause 55/55 is 1

Answer 37

now multiply that to the other side so you will get?

Answer 38

55*cos(49) = 36.083246594505, is that right? I usually get this part wrong, sorry!

Answer 39

Remember to round

Answer 40

thats not what I got

Answer 41

oh im on radian

Answer 42

just a sec

Answer 43

I won't @ShadowLegendX ^-^

Answer 44

alright kayders :)

Answer 45

Yes that is what I got

Answer 46

http://www.wolframalpha.com/input/?i=55cos(49)

Answer 47

Itʻs correct

Answer 48

:)

Answer 49

@Cresciez Do we need to round?

Answer 50

Yes we do, to the nearest hundredth - I think it's 36.083?

Answer 51

or just 36?

Answer 52

to the nearest hundredth is 2 places after the decimal

Answer 53

so 36.08? o.O

Answer 54

yes! :)

Answer 55

thank you so much for your patience and help! you too @ShadowLegendX ^.^

Answer 56

If you need more help I would be happy to help, I hope you understood what is going on a little bit better :)

Answer 57

^

Answer 58

Thank you both! I have two more questions but I'll open up a new thread for each. Does that sound alright?

Answer 59

yeah!

Answer 60

great! :D