Unable to solve this Trig question

ak1992

I have been trying for hours to solve this problem however I am unable to use any trig function to solve the problem.

I am trying to find out the diameter of the circular tank.

From point X to the start of tank is 101.527M (Which on photo is marked with an X and a arrow) 20150718_002426[1].jpg

The Angle AXO is 17'10'40"
Angle XAO is 90'

I have tried going down the similar triangle route however I didn't have much luck.

I have attached a photo and any help would be much appreciated.

(edited 8 years ago)

Reply 1

DrAdrenaline

14

Original post by ak1992

I have been trying for hours to solve this problem however I am unable to use any trig function to solve the problem. I am trying to find out the diameter of the circular tank.From point X to the tank is 101.527M (Which on photo is labeled R)20150718_002426[1].jpgThe Angle AXO is 17'10'40"Angle XAO is 90'I have tried going down the similar triangle route however I didn't have much luck. I have attached a photo and any help would be much appreciated.

what do you mean by 17'10'40''?

can't you just find OA and x2 for the diameter.

(edited 8 years ago)

Reply 2

ak1992

OP

2

17 degrees 10 minutes 40 seconds

Reply 3

cacra

15

Original post by swopnil

what do you mean by 17'10'40''?

can't you just find OA and x2 for the diameter.

17.1777... degrees iirc.

Reply 4

ak1992

OP

2

Original post by swopnil

what do you mean by 17'10'40''?

can't you just find OA and x2 for the diameter.

How am I able to find OA?

I have only been given the length 101.527M which is to the edge of the tank marked with a X and a arrow

Reply 5

Shadez

10

Original post by ak1992

x.

adding to what @swopnil said if the answer is 60 m^2 just use SOH CAH TOA after converting 17 degrees 10 minutes and 40 seconds into decimal degrees

Edit: Ignore what I've just said didn't read the question properly

(edited 8 years ago)

Reply 6

ak1992

OP

2

Original post by Shadez

adding to what @swopnil said if the answer is 60 m^2 just use SOH CAH TOA after converting 17 degrees 10 minutes and 40 seconds into decimal degrees

17 degrees 10 minutes 40 seconds is just 17.1777 degrees.

Where did 60m^2 come from?

Reply 7

Shadez

10

Original post by ak1992

17 degrees 10 minutes 40 seconds is just 17.1777 degrees.

Where did 60m^2 come from?

apologies I didn't read the question properly

Reply 8

DrAdrenaline

14

Original post by ak1992

How am I able to find OA?

I have only been given the length 101.527M which is to the edge of the tank marked with a X and a arrow

oh okey. i think i got it now. is the answer 83.896...?

Reply 9

Absent Agent

21

Original post by Shadez

adding to what @swopnil said if the answer is 60 m^2 just use SOH CAH TOA after converting 17 degrees 10 minutes and 40 seconds into decimal degrees

Edit: Ignore what I've just said didn't read the question properly

what you've said is correct. whats wrong with the question?

Reply 10

ak1992

OP

2

Original post by swopnil

oh okey. i think i got it now. is the answer 83.896...?

How did you work that out?

Reply 11

Shadez

10

Original post by Mehrdad jafari

what you've said is correct. whats wrong with the question?

From point X to the tank is 101.527M (Which on photo is labeled R)

I assumed it was to the centre of the tank

Reply 12

DrAdrenaline

14

Original post by ak1992

How did you work that out?

is it right? i got confused about the '17 degrees 10 minutes 40 seconds' business and just used 17 degrees as the angle.

sin 17 = r/101.527+r

Reply 13

ARotchell

ImageUploadedByStudent Room1437177587.024287.jpg

I agree with 83.896... just used the angle as 17 degrees exactly so might be a little inaccurate... it might be wrong altogether, it is quite late!

Posted from TSR Mobile

Reply 14

Shadez

10

Original post by swopnil

is it right? i got confused about the '17 degrees 10 minutes 40 seconds' business and just used 17 degrees as the angle.

sin 17 = r/101.527+r

I got 89.2

Spoiler

(edited 8 years ago)

Reply 15

ak1992

OP

2

Original post by Shadez

From point X to the tank is 101.527M (Which on photo is labeled R)

I assumed it was to the centre of the tank

Sorry I didn't explain it well. 101.527M is to where the centre line from X meets the circle.

Reply 16

Choppie

14

(Using the top triangle)

101.527 (XO) = hyp
XA = adj
OA = opp = radius

Two steps:

cos(17deg) = adj/hyp. Therefore, adj = hyp * cos(17deg) = 97.09
So XA = 97.09

Now

tan(17deg) = opp/adj. Therefore, adj * tan(17deg) = opp = 29.68
OA = 29.68 = radius
Radius = diameter * 2, so...

Diameter = 29.68*2 = 59.36m

Reply 17

DrAdrenaline

14

Original post by Shadez

I got 89.2

Spoiler

okey fair enough, you used 17.7778, you are probably more right

Reply 18

Shadez

10

Original post by ak1992

Sorry I didn't explain it well. 101.527M is to where the centre line from X meets the circle.

No worries someone's posted a seemingly correct solution for you hope that clears it up :smile:

if not ask away

Reply 19

Shadez

10

Original post by Choppie

(Using the top triangle)

101.527 (XO) = hyp
XA = adj
OA = opp = radius

Two steps:

cos(17deg) = adj/hyp. Therefore, adj = hyp * cos(17deg) = 97.09
So XA = 97.09

Now

tan(17deg) = opp/adj. Therefore, adj * tan(17deg) = opp = 29.68
OA = 29.68 = radius
Radius = diameter * 2, so...

Diameter = 29.68*2 = 59.36m

I thought this too but 101.527 is OR, where R is the edge of the tank

Unable to solve this Trig question

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