Qualification > Math
IGCSE MATHS Doubts
ksitna:
kk i know u guys are gonna kill me but
well i dont get this question either
A cylindrical glass has a radius of 3 centimetres and a height of 7 centimetres.
A large cylindrical jar full of water is a similar shape to the glass.
The glass can be filled with water from the jar exactly 216 times.
Work out the radius and height of the jar.
Ghost Of Highbury:
Volume of glass = Pi*r2*h = 63Pi
so volume of jar = 216* 63Pi = 13608Pi cm3
since jar is similar shape to glass then ratio of height / radius of the jar = 7/3
let height of jar = h cm
h/r = 7/3
r/h = 3/7
r = 3h/7
volume of jar = Pi *(3h/7)2*h
= 9h2/49 * h * Pi
= ( 9/49)*h3* Pi
so (9/49)*h3* Pi = 13608Pi
h^3 = 13608*(49/ 9)
h = 42 => r = 42 * 3/7 = 18
r = 18 cm and h = 42 cm
ksitna:
thank youuuu ;D
idrees:
um i asked this Q .. really no one helped
can someone please explain the question
june 2007 p4 q7
--- Quote from: idrees on May 08, 2010, 06:48:34 pm ---hey i really need help with this Q.
its killing me! if someone could just explain the dynamics of this q .. how do i go about solving the question. thats all i need .. im really good at mensuration, i have just forgotten how to solve questions regarding rate of flow of water ..
June 2007 p4 Q7
Thanks a LOT!
--- End quote ---
Vin:
--- Quote from: idrees on May 08, 2010, 09:40:04 pm ---um i asked this Q .. really no one helped
can someone please explain the question
june 2007 p4 q7
--- End quote ---
sure .. gimme some time .. :)
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