Qualification > Math
IGCSE MATHS Doubts
Ghost Of Highbury:
5/4 = 1.25
1.25 * 44 = 55
1.25 * 32 = 40
55, 40
Baladya:
A statue two metres high has a volume of five cubic metres.
A similar model of the statue has a height of four centimetres.
(a) Calculate the volume of the model statue in cubic centimetres.
Anyone :D?
Ghost Of Highbury:
--- Quote from: contraentry on May 05, 2010, 03:48:17 pm ---I have stumbled upon a slight issue in solving one of the Paper 4's, could someone please explain how to go about solving this ?
part (d) & (e) of question 5, on the attached sheet.
--- End quote ---
Ok here goes the (d) part.
Let midpoint of the chord be G,perpendicular from centre bisects the chord AC.
Now AG = 1.8 m
Now two right angled triangles AOF and AGE are similar, therefore their corresponding sides will be proportional
OA/AG= AF/GE
2/1.8=5/GE
GE=(5*1.8)/2 = 4.5 m
CHeck the attached image.
e) Consider the triangle OGC. OG = = 0.87
Let the point where GE intersects the circle be M.
MG = 2 + 0.87 = 2.87
Thus ME = 4.5 - 2.87 = 1.63
OE = ME + OM = 3.63
OD = =
Consider the right angled triangle ODE. OE = 3.63, OD = , thus
ED = = 3.97
FE = ED = 3.97
FD = 8 (app.)
Area of trapezium = 0.5* (3.6+8)*4.5 = 26.1
Area of whole Shape = 26.1 + Area of the semi-circle ABC.
Area of semi-circle ABC = 2.913
Thus the area of the whole shape = 29cm^2
haris94:
--- Quote from: Baladya on May 05, 2010, 05:52:48 pm ---A statue two metres high has a volume of five cubic metres.
A similar model of the statue has a height of four centimetres.
(a) Calculate the volume of the model statue in cubic centimetres.
Anyone :D?
--- End quote ---
V1/V2 = (l1/l2)3
so
5/v2 = (2/0.4)3
v2 = 5*(0.4)3
(2)3
v2 = 0.04m3
0.04*1000
=40 cm3
contraentry:
Wow, thanks A@di, this is really simple to understand now... I took a more complicated approach, and arrived at the answer, but this pretty much sums it all up!
Once again, thank you so much! :) :)
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