Question

Bob is driving along a straight and level road straight toward a mountain. At some point on his trip he measures the angle of elevation to the top of the mountain and finds it to be 21°44'. Find the height of the mountain to the nearest foot if Bob is 13,474.3 feet from the center of the mountain at the base.

Answer 1

tan(21+44/60)=-2.63668....?

Answer 2

No. Everything I do ends up giving me a completely different answer than any of the possible choices. I see what you mean about finding AB I think. It is basically what value of ab divided by 13474.3 gives you tan21′44′′ right?

Answer 3

the choices are

5453 ft
5353 ft
53,534 ft
535,342 ft

I think it is 5353ft.

Answer 4

:) Haha its ok. You're helping me out a ton. Take your time.

Answer 5

I keep getting 6871.0846. I did (sin21′44′′)*13474.3 and then doubled it.

Answer 6

:( That's not one of the choices. The choices are
5453 ft

5353 ft

53,534 ft

535,342 ft

Don't ask me how my teacher got those but those are the multiple choice answers he gave me.

Answer 7

I'm glad I'm not the only one making mistakes. It makes me feel better that you are too. :P

Answer 8

Now I'm seriously lost. Do I have to multiply by 4 now?

Answer 9

I have no idea what to do here.

Answer 10

in triangle BDC , tan x = BD/BC

Answer 11

in triangle BDC , tan x = BD/BC

Answer 12

now BD=AD
so we can write , tan x= AD/BC -------------> 1.)

in triangle ABC, tan21'44''=AB/BC
now, AB=2AD
so, tan21'44'' = 2AD/BC
or , tan21'44'' / 2 = AD/BC -----------------> 2.)

since the RHS of 1.) and 2.) are equal, their LHS must be equal,
so, tan x = tan21'44''/2

find x.

understood uptil now ??

Answer 13

Wow, I ended up getting 7.1216. I am so completely lost now. What happened to 13474.3?

Answer 14

is it positive value of negative of x?

Answer 15

I don't know. I guess negative?

Answer 16

now , use sin x.

Answer 17

I don't even know what x is anymore.

Answer 18

7.1216.

Answer 19

You mean that was right?

Answer 20

i have doubt how it can be negative.

Answer 21

OK well sin(7.1216)=.743584.........

Answer 22

check your sin value

Answer 23

I thought you said it was 7.1216?

Answer 24

sin(7.1216)=0.123976............

Answer 25

How did you get that? My calculator keeps saying .743584... so on. Maybe that's my problem. My calculator is broken?

Answer 26

http://www.wolframalpha.com/input/?i=sin%287.1216%29

Answer 27

OH degree! Oh. I see.

Answer 28

i get this strange feeling that something in that triangle is wrong....

Answer 29

Oh my f******. I'm never going to get this. I really appreciate your help but at this rate, there is no way I'm picking this up. I am too lost and just completely burnt out on this entire question. I have a million more just like it and its been like 3 hours on the same question. I have no idea what I'm doing with this.

Answer 30

i am getting it as 5371.1
tan 21.44 * 13474.3.
and nearest option is 5353 ft

Answer 31

Doing it that way I got 5291.3576. Close enough. Thats the answer I choose 5353. I give up. Thank you guys for your help. I really do appreciate it. I know im not an easy one teach.

Answer 32

yeah, don't waste much time on one problem, go to next