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betme
23 Mar 15 20:52
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Date Joined: 11 Jul 02
| Topic/replies: 2,205 | Blogger: betme's blog
My my daughter needs to know how to work this math out.in a photograph the heights of 3 girls are 10cm, 9cm, and 7cm. The scale of the photo is 1:16 ,What is the real height of the tallest girl answer in metres.
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Report David Fishwick Minibus Sales March 23, 2015 7:54 PM GMT
Cry
Report Mikael D'Haguenet March 23, 2015 7:54 PM GMT
Cry
Report lumponlarge March 23, 2015 7:57 PM GMT
Tallest Girl in Photo = 10 cm
Multiply by Scale of Photo = 16
... so real height is 10 x 16 = 160 cm

How can you not crack this poser is a mystery, I must say.
Report doantwin2easy March 23, 2015 8:00 PM GMT
i.e. 1.6 metres
Report Make my hay March 23, 2015 8:03 PM GMT
5.24934383 feet
Report brendanuk1 March 23, 2015 8:07 PM GMT
1:16 is imperial so you will have to convert it to metric to work with cm, hth
Report Make my hay March 23, 2015 8:10 PM GMT
Yes but is the 10cm   girl wearing shoes with bigger  heels than the other two girls?
Report brendanuk1 March 23, 2015 8:12 PM GMT
or one on a step
Report Make my hay March 23, 2015 8:14 PM GMT
or 7cm girl standing in a pothole.
Report Make my hay March 23, 2015 8:19 PM GMT
or in the distance.
Report s.kenbo March 23, 2015 8:32 PM GMT
Primary school maths is a bitch!!
Report akabula March 23, 2015 8:41 PM GMT
Trawling surely.
Report Just Checking March 23, 2015 8:47 PM GMT
You'd have to know the distance to the camera, that scale would only be correct at one specific distance.

But I doubt it's that technical for kids!
Report Capt__F March 23, 2015 10:10 PM GMT
is it the ISIS girls ?
Report donny osmond March 23, 2015 10:13 PM GMT
scale 1:16

she could be 10/16 of a cm tall
Report naydam March 23, 2015 10:26 PM GMT
Confused
Report blackbarn March 23, 2015 10:44 PM GMT
I cannot believe how insensitively this gentleman has been treated on here. He was clearly brought up on imperial measurement and is struggling, as many of us older ones do, with getting the decimal point correctly placed when factoring up these minor decimal metrics. It is clear that the tallest young lady is almost exactly 52ft high. Hope this helps.
Report Just Checking March 23, 2015 10:44 PM GMT
There was an documentary a couple of years ago about how in ww2 they could work out the height of V2 rockets by looking at the shadow on aerial photos, knowing the angle the sun would be at that time of day and doing the maths. Get the kids working on that Laugh.
Report ebulGery March 23, 2015 10:46 PM GMT
1.6 metres
Report blackbarn March 23, 2015 10:48 PM GMT
Ebulgery - Nice one Einstein!!  You should be somewhere else.
Report Mikael D'Haguenet March 23, 2015 10:48 PM GMT
Blackbarn Laugh
Report ebulGery March 23, 2015 10:50 PM GMT
It is hardly difficult
Report Mikael D'Haguenet March 23, 2015 10:50 PM GMT
That was to your 22:44 post btw.
Report blackbarn March 23, 2015 10:52 PM GMT
Forgive me Ebulgery, but I think that might be the central point of several posts on here ahead of yours.  Still, if it makes you happy.
Report David Fishwick Minibus Sales March 23, 2015 10:52 PM GMT
Capt__F    23 Mar 15 22:10 
is it the ISIS girls ?


ISO girls shirley?
Report blackbarn March 23, 2015 10:54 PM GMT
Thanks Mikael. Noted!
Report ebulGery March 23, 2015 10:56 PM GMT
Just Checking  • March 23, 2015 10:44 PM GMT 


There was an documentary a couple of years ago about how in ww2 they could work out the height of V2 rockets by looking at the shadow on aerial photos, knowing the angle the sun would be at that time of day and doing the maths. Get the kids working on that Laugh.


incredibly simple as well
Report blackbarn March 23, 2015 11:03 PM GMT
Ebulgery - not quite on the same scale as multiplying 10cm by 16, but again if it keeps you happy, stick with it.
Report ebulGery March 24, 2015 1:43 AM GMT
I spent a lot of time solving that...I thought I was clever

oh wellCry
Report ebulGery March 24, 2015 1:45 AM GMT
It was not just 16 X 10
you forgot the division by 100...immensely trickyLaugh
Report naydam March 24, 2015 1:49 AM GMT
Ebulgery. It's not all simple, really. It's not a simple matter of a bit of trig. The problem is that you don't know the actual length of the shadow either. The apparent size of the shadow depends upon the camera specifics and the altitude of the aircraft carrying the camera.

One thing they used to look for, specifically, was cricket pitches. You could easily detect the wicket zones which were always 22yds apart and so they could scale things directly.
I didn't know that the Germans even played cricket!  ShockedLaugh
Report ebulGery March 24, 2015 11:01 AM GMT
I was assuming the plane had an altitude meter, it knows it's own height above the ground, the angle of the sun
from that the length of the shadow can be deduced and thus height of rocket, basic trig

still I thought I was being clever get the answer to the OP problemLaugh
Report ebulGery March 24, 2015 11:18 AM GMT
Actually I am not so sure about that now Naydam, the shadow, a long time since I was at school
I will think about it later, more important stuff, now this afternoon's greyhounds
Report naydam March 24, 2015 11:29 AM GMT
You need the altitude, the geographical location, the camera characteristics (focal length, I think), the time of day and the apparent length of the shadow. Oh, and a pencil and a bit of paper! Laugh


AND those Log tables that you threw out years ago!  Cool
Report ebulGery March 24, 2015 3:54 PM GMT
I will take back my remark about it being incredible simpleBlush
Report mememe March 24, 2015 4:25 PM GMT
Were the 3 girls straight A students?

And if they weren't all in a straight line as well, then it affects the answer, because it's a lot more difficult.

You need to know Pythagoras like the back of you hand to work it out properly, or do like I do when selecting a lay bet, take Pi as being 22/7 (and don't worry about the square root of -1 ... ignore it for the purposes of this question).
Report naydam March 24, 2015 5:12 PM GMT
If the girls WERE in a straight line...that would complicate matters severely. Much easier if they are positioned in an arc. Devil
Report brendanuk1 March 24, 2015 5:25 PM GMT
Noah's Arc Confused
Report s.kenbo March 24, 2015 6:33 PM GMT
Blackbarn. LaughLaughLaugh
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