2008 mathematics school certificate..emergency very tricky questions mostly geometry (1 Viewer)

[Riot09]

<HR style="COLOR: #d1d1e1; BACKGROUND-COLOR: #d1d1e1" SIZE=1><!-- google_ad_section_start -->please include working out and a explanation all the diagram question can be found on the link below.

http://www.boardofstudies.nsw.edu.au...athematics.pdf

q.22the circumference of this circle is 31.4.the diameter is 10cm.

calculate the perimeter of the shaded semi-circle.(without a calculator)

q.32 is a diagram question

q.41,43,46,56,59,62,64,65,66,67,70,71,72,73,75,80, 81 and 83 would be greatly appreciated<!-- google_ad_section_end --></SPAN>

 

[Amogh]

Re: 2008 mathematics school certificate..emergency very tricky questions mostly geome

dude this is getting hectic.
i'll answer later if i get free time.

 

[Riot09]

Re: 2008 mathematics school certificate..emergency very tricky questions mostly geome

alright,thanx anyway

 

[Absolutezero]

Re: 2008 mathematics school certificate..emergency very tricky questions mostly geome

I've done them all except the last two here:

http://community.boredofstudies.org...on-calculator-questions-help.html#post4625423

This is the last post in a whole bunch which answers them.

 

[with-chu]

Re: 2008 mathematics school certificate..emergency very tricky questions mostly geome

<HR style="COLOR: #d1d1e1; BACKGROUND-COLOR: #d1d1e1" SIZE=1><!-- google_ad_section_start -->please include working out and a explanation all the diagram question can be found on the link below.

http://www.boardofstudies.nsw.edu.au...athematics.pdf

q.22the circumference of this circle is 31.4.the diameter is 10cm.

calculate the perimeter of the shaded semi-circle.(without a calculator)

q.32 is a diagram question

q.41,43,46,56,59,62,64,65,66,67,70,71,72,73,75,80, 81 and 83 would be greatly appreciated<!-- google_ad_section_end --></SPAN>

Dude........ that's like half the paper.

I did the circle Q - the rest I cbb.
It's Q23 by the way, not 22.

To get the perimeter, you need to figure out two lengths - the curved part and the straight part of the circle.

You get the length of the curved part of the semicircle by dividing the circumference by two:
31.4/2 = 15.7

and you add the length of the straight part of the semicircle (diameter) to the number above:
15.7+10=25.7cm

 

[supre]

Re: 2008 mathematics school certificate..emergency very tricky questions mostly geome

32. its cos y because sin x=4/5 and cos y is the same (C)
43. treadmill has 3 sections so divide 24/3 thats 8 and in total the bar has 10 sections so 8*10=80 (C)
46. (C)

i will do the rest in a while...

 

[Riot09]

Re: 2008 mathematics school certificate..emergency very tricky questions mostly geome

thanx,very big help

 

[Amogh]

Re: 2008 mathematics school certificate..emergency very tricky questions mostly geome

q.22the circumference of this circle is 31.4.the diameter is 10cm.

calculate the perimeter of the shaded semi-circle.(without a calculator)
Perimeter is half the circumference + the diameter
31.4/2 + 10=...

q.32 is a diagram question
sinx=4/5(Opposite/Hypotenuse)
cosy=4/5 (Adjacent/Hypotenuse)
hence sinx = cosy

q.41
cost of text = 3*25 = $0.75
4 minutes and 35 sec= 275 s
now its 'part there of' so even though its only 5 seconds more than 9, 30 seconds, it is counted as a whole. So 275/30 = 9.16 but the .16 becomes a whole and makes it 10. Ambiguous explanation. Could someone help me?
cost of call= 0.27 + 10*0.385
total = cost of text + cost of call


43
3 segments (Treadmill)= 24 minutes
1 segment (Weight) = 24/3 = 8
2 segment (Rowing Machine)= 24/3 * 2= 16
4 segment (Bike) = 24/3 *4 = 32
Total time spent = 80 minutes

45
Im not sure but i think you draw a grid over the diagram. Does anyone know another method?


46
Find the value of each can per unit gram.
For example for the first one: cost of one gram = 2.80/125 dollars
Do the same for all. Then see which one is of the best value.


47
P(green) = Time it is green/Total possible outcomes = 30/45+5+30 = 30/80


56
the 70 degree angle and another angle make 360 (One circle)
so the last unknown angle (apart from the y) is 360-70 = 90
now add all the known angles in the quadrilateral and subtract it from 360.

59
4 squares (s) = 3 triangles (t) --1
5 circles (c) = 2 t --2
so one t = 4/3 s and 5/2 c (From 1 and 2)
T is thus definitely the largest.
now s=3/4 t and c=2/5 t
so s is larger than c
Hence the order from Largest to Smalles = T, S, C

62
Enlargement factor is 60/3 =20(They are similar figures, and be careful while deciding which sides are meant to be in the same ratio)


64,65,66,67,70,71,72,73,75,80, 81 and 83 later, hopefully

 

[Riot09]

Re: 2008 mathematics school certificate..emergency very tricky questions mostly geome

question 81,1,000,000 points to the Winner

 

[Top Secret]

Re: 2008 mathematics school certificate..emergency very tricky questions mostly geome

question 81,1,000,000 points to the Winner

81.

(a) sin@ = opp / hyp = 27 / 120
@ = sin inverse 27 / 120
= 13 degrees

(b) sin 33 = (76-27) / BD
BD = sin inverse 49 / sin 33
= 90 m

(c) Total distance = (120 + 90) m
= 210 m
Velocity = 210 m / 75 sec
= 2.8 m/s

---

Now, where are ma points?

 

[Xcelz]

Re: 2008 mathematics school certificate..emergency very tricky questions mostly geome

question 81,1,000,000 points to the Winner

part (a)
angle of elevation = theta
sin theta = BC/AB
sin theta = 27/120
theta = sin^-1 (27/120)

theta = 13 degrees, 0 minutes, 10.36 seconds

(b)
DE = 76- 27
DE = 49m
sin 33degrees = DE/BD
sin33degrees = 49/BD
BD=49/sin33degrees
BD= 89.9....m so round off to approx 90m

(c)
so speed = distance/time (s=d/t)
distance = 90+120= 210m
t = 1min 15 sec = 75 seconds

so now speed = 210/75
= 2.8 m/s

 

[Absolutezero]

Re: 2008 mathematics school certificate..emergency very tricky questions mostly geome

^lol.

I would have done it, but I don't have a calculator on me.

 

[Top Secret]

Re: 2008 mathematics school certificate..emergency very tricky questions mostly geome

^lol.

I would have done it, but I don't have a calculator on me.

Well I just used the Windows Calculator.

 

[allira92]

Re: 2008 mathematics school certificate..emergency very tricky questions mostly geome

... i miss year 10 maths...

 

[Absolutezero]

Re: 2008 mathematics school certificate..emergency very tricky questions mostly geome

Well I just used the Windows Calculator.<!-- google_ad_section_end --></SPAN>

As in the scientific one? I didn't even check to see if it had inverse sin. I was about to leave my computer anyway at the time though.

 

[h3ll h0und]

Re: 2008 mathematics school certificate..emergency very tricky questions mostly geome

... i miss year 10 maths...

i miss year 10

 

[Riot09]

Re: 2008 mathematics school certificate..emergency very tricky questions mostly geome

ill add a reputation point to youre profile

 

[ninetypercent]

Re: 2008 mathematics school certificate..emergency very tricky questions mostly geome

i miss year 10

I don't. I miss Year 11.

 

[h3ll h0und]

Re: 2008 mathematics school certificate..emergency very tricky questions mostly geome

i miss not being in yr 12