Question

Find x
A. 9
B. 18
C. 9√3
D. 3√3

Answer 1

The equation?

Answer 2

http://roads.advancedacademics.com/contentserver/content/roadssection/279450/questions/assessments/t-righttrianglespythagoreantheoremquiz/geometry_4.3_quiz_10q.gif

Answer 3

We will be using Tangent. x is the hypotenuse and 9 is the opposite. 30 is the theta:

\[tan30 = \frac {9}{x}\]

Answer 4

\[tan30 \approx 0.577\]

Answer 5

\[0.577 \approx \frac {9}{x}\]
Multiply x on both sides. then divide tan30 on both sides and solve.
\[(0.577)(x) \approx 9\]
\[x \approx \frac {9}{0.577}\]
\[x \approx 15.59\]

Answer 6

Hmm, I think I did something wrong.

Answer 7

haha thanks for helping me tho. I am having trouble with this unit

Answer 8

do you have any other idea on how to do this?

Answer 9

Yeah I'm kind of confused as well. >.<

Answer 10

haha ok thanks anyways. Do you know of anyone else who can help?

Answer 11

@thomaster

Answer 12

OOOOH I see what I did wrong. I needed to use sine and not tangent.

Answer 13

sin30 = 0.5

9/0.5 = 18

Answer 14

Ha, silly me. :P

Answer 15

haha thank you so much!

Answer 16

can you help with one more?

Answer 17

sure

Answer 18

Using SOH CAH TOA, do you know which triginomic ratio we need to use? Cosine, sine or tangent?

Answer 19

wow this is making me see how truly bad i am at this... im not really sure... promise im not just tryin to get answers haha

Answer 20

oh and the options are
A.9

Answer 21

B. 9√2
C.4.5√2
D. 18√2

Answer 22

SOH means: sine = opossite/hypotenuse
CAH means: cosine = adjacent/hypotenuse
TOA means: tangent = opposite/adjacent

They are abbreviations. We have the opposite measurement and are looking for the adjacent. So which ratio do we need to use?

Answer 23

TOA?

Answer 24

Yes. We are going to use the tangent. So:
\[tan45 = \frac {18}{x}\]
Do you know how to find x?

Answer 25

ugh. no not quite

Answer 26

Well we learned in previous math lessons that to find a missing variable you need to isolate the unknown variable. So in this case we need to find a way to move the "x" so that it is by itself. Are you understanding so far?

Answer 27

ya i understand what you r saying

Answer 28

But we need to know what tan45 is. But we can't do that calculation so quickly, which is why we have calculators. Do you know how to find tan45 with a calculator? :3

Answer 29

no

Answer 30

Some calculators are different. Do you have one at home?

Answer 31

ya

Answer 32

Ok, are there tan, cos and sin buttons on it?

Answer 33

is it 1?
i put 45 tan

Answer 34

Yep!

Answer 35

yay
i actually got something right! haha

Answer 36

So now we have:
\[1 = \frac {9}{x}\]
So now let's isolate the x. What's the first step?

Answer 37

multiplying 9 and 1?

Answer 38

Nope, because x is the denominator then we must multiply x on both sides. That gives us 1x on the left, but what will happen on the right?

Answer 39

oh ok..... 9x? i have no idea

Answer 40

Since it's already being divided by x, it will be canceled out by the multiplication. So now we have:
\[1x = 9\]
What is the last step?

Answer 41

oh ok i see.

Answer 42

umm devide 1 and 9 so its 9

Answer 43

Yes. So x = 9.

And to check, we have to make sure that tan45 = 9/9

tan45 = 1
x = 9

1 = 9/9
1 = 1

:D

Answer 44

yay thank you so much!!!

Answer 45

Aaaah I mixed up 18 with 9 somehow. .-.

Answer 46

Hold on xD

Answer 47

1 = 18/x
1x = 18
x = 18/1
x = 18
1 = 18/18
1 = 1

Yeah xD

Answer 48

so i was right with 9?

Answer 49

Omg I'm so stupid 18 was the hypotenuse .-.