ATAR Notes: Forum
Archived Discussion => 2010 => End-of-year exams => Exam Discussion => Victoria => Further Mathematics => Topic started by: pirocan1 on November 03, 2010, 04:30:46 pm
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Is it 8.55 or 6.54??
I got different answers for the different lengths i used...
What a stupid question, it didnt even tell you to how many decimal places.
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Some have also said 7.55.
I believe it is 7.55 finding the ratio then multiplying it by the height and then adding either 4 or 3 ( dont remember ), all I know is that I only got 1/2 since I didnt add the height >.<
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I got the scale factor of 1.46 and used that to get 6. something.. but ive been reading around and everyone got different answers so im probably wrong haha
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Yea everyone keeps saying, 7.55 so im thinking thats it...
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I believe it is 7.75, as solved by my calculator.
If you calculate the area of the whole trapezium, it is 1360. Then:
1360 = Area of left trapezium + Area of right trapezium
Solve for x, and you get 7.75.
Easy!
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the easiest way was to use trigonometric ratios. Because the angle between the smaller and larger triangle is the same. Then finding the angle u use it to find the height of smaller triangle which is in turn 3.25 , add that to 4.5 and u get 7.75. sweet. i was so happy with that question.
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i got 7.75 or 7.55 cant remember. It was 7 something
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i did..
12.5:95
x:65
hence, x=(12.5*65)/95= 8.55
how did people get 7.55..?
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theres the thing its nopt 12.5 to 95. because thats not a triangle. its 12.5: 160
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7.75!!
definitely!
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12.5:160 isn't a triangle either
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I had no idea how to do it.
So I used a different method.
I found the gradient of the slope and subbed in the value of H.
Wrong section I know but still got the answer: 7.75
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it was 8: 160
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8/160 = x/65
x = 3.25
3.25 + 4.5 = 7.75
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the easiest way was to use trigonometric ratios. Because the angle between the smaller and larger triangle is the same. Then finding the angle u use it to find the height of smaller triangle which is in turn 3.25 , add that to 4.5 and u get 7.75. sweet. i was so happy with that question.
thats what i did :)
took me like bloody 10 minutes... was staring at that bloody question for like yonks..
teacher reckons it was a good method :D
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i did spesh, and methods, and further
and i am 150% sure its 7.75...
hell yeees
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yeh sorry. thats wat io meant 8, because 12.5 -4.5 gave u 8. sorry thats wat i did. i cudn't remember the question.
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so would i get a consequential mark for using ratios? :)
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7.75! :)
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I don't at all remember what I wrote but I'm sure it was wrong. If I could see the paper I might remember what I wrote =/
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5.08
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I think I was the only person who calculated the area and found it. Weird. Seemed logical to me lol :P
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5.08
That's what I got too :(.
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isn't that the answer?
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nah its definately 7.75m
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Would you get one mark for forgetting to add the 4? Stupid mistake I know :(
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also, the question asked you to find the value without specifying how many digits to round it off to, indicating that the answer you'd get would be exact, true?
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For the flying fox Question.
I did 12.5/95 = PH/65 ---> to work out PH, and got 8.55m.
What did I do wrong here??
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only the triangle on top is similar you cannot use the whole shape
The CORRECT answer is 7.75M
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I used the gradient method to get 7.75 and checked with the ratio thingo.
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Yer i used TAN to find the angle in the triangle, and tan again to find the height in the middle and added the height of the square at the bottom
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LOL its 7.75.
im probably the only one in the state that solved it this way, but i worked out the EQUATION of the line and it was y=-0.5x+12.5.
then simply sub in 95 and wallah!!! 7.75
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LOL its 7.75.
im probably the only one in the state that solved it this way, but i worked out the EQUATION of the line and it was y=-0.5x+12.5.
then simply sub in 95 and wallah!!! 7.75
LOL its 7.75.
im probably the only one in the state that solved it this way, but i worked out the EQUATION of the line and it was y=-0.5x+12.5.
then simply sub in 95 and wallah!!! 7.75
wow, thats quite pro, gotta admit
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:o :idiot2:
LOL its 7.75.
im probably the only one in the state that solved it this way, but i worked out the EQUATION of the line and it was y=-0.5x+12.5.
then simply sub in 95 and wallah!!! 7.75
how did you deduce the equation of the line??? and using that actually comes up as -35. :buck2:
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LOL its 7.75.
im probably the only one in the state that solved it this way, but i worked out the EQUATION of the line and it was y=-0.5x+12.5.
then simply sub in 95 and wallah!!! 7.75
Yeah, used the same method, but you could've used stacks of different ways.
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:o :idiot2:
LOL its 7.75.
im probably the only one in the state that solved it this way, but i worked out the EQUATION of the line and it was y=-0.5x+12.5.
then simply sub in 95 and wallah!!! 7.75
how did you deduce the equation of the line??? and using that actually comes up as -35. :buck2:
Used the same method, lol but as I said somewhere else. We'll probably lose a mark since we were SUPPOSED to use similar triangles.. (Geometry section lol, not graphs/relations haha).
Anyway to actually achieve this, let T = 0.
So you have the very left side where the flying fox is located at the top of the hill, and since that's x=0, the y value is the height.
So: (0,12.5)
Then do the same with the other end. (160,4.5) since 160m from T and 4.5m high.
Now you have two points:
(0,12.5)
(160,4.5)
Use m=y2-y1/x2-x1
And you get -0.05.
Then y-y1=m(x-x1)
to get C value which turns out to be: c=12.5
So the equation you're left with: y=-0.05x + 12.5
Sub in value of H (95m)
And you get: 7.75m
Done.
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:o :idiot2:
LOL its 7.75.
im probably the only one in the state that solved it this way, but i worked out the EQUATION of the line and it was y=-0.5x+12.5.
then simply sub in 95 and wallah!!! 7.75
how did you deduce the equation of the line??? and using that actually comes up as -35. :buck2:
Used the same method, lol but as I said somewhere else. We'll probably lose a mark since we were SUPPOSED to use similar triangles.. (Geometry section lol, not graphs/relations haha).
Anyway to actually achieve this, let T = 0.
So you have the very left side where the flying fox is located at the top of the hill, and since that's x=0, the y value is the height.
So: (0,12.5)
Then do the same with the other end. (160,4.5) since 160m from T and 4.5m high.
Now you have two points:
(0,12.5)
(160,4.5)
Use m=y2-y1/x2-x1
And you get -0.05.
Then y-y1=m(x-x1)
to get C value which turns out to be: c=12.5
So the equation you're left with: y=-0.05x + 12.5
Sub in value of H (95m)
And you get: 7.75m
Done.
Didn't specify which method and it's Further, not methods. I'd say 7.75 with any working would get 2 marks