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 Nov 14th 2017, 05:36 AM #1 Junior Member   Join Date: Nov 2017 Posts: 4 Please help! How big does the semi circle need to be? Hello there, The problem that one of my students came to me with is: I want to fit 240 grams of chocolate into a semi circle, so could you tell me the diameter I need to make the semi circle in mm? I have worked out that the volume of a 100mm diameter semi circle is 5235 cubic mm, but then how do I apply that? Please help! Many thanks!
 Nov 14th 2017, 06:50 AM #2 Senior Member     Join Date: Jun 2016 Location: England Posts: 366 I note that You seem to have had some problems posting... There is some crucial information missing What is the volume of 240 grams of chocolate? litres would be a start, but then that would need to be converted to cubic mm to fit with the other part of your solution. __________________ ~\o/~
Nov 14th 2017, 06:36 PM   #3
Senior Member

Join Date: Apr 2017
Posts: 157
 Originally Posted by JJLondon I have worked out that the volume of a 100mm diameter semi circle is 5235 cubic mm, but then how do I apply that?!
First we need to need to understand the difference between AREA and VOLUME

A 100mm circle has an AREA of 78.5 square centimeters it only has a VOLUME when height is specified ...

You need to tell us how thick the chocolate will be ,

Solid chocolate has a density of 1.056

 Nov 15th 2017, 02:25 AM #4 Junior Member   Join Date: Nov 2017 Posts: 4 How do I go about finding the volume of a material? Such as chocolate, wax or Ink as examples..? And sorry, i'm talking about a sphere and semi sphere, so the height of the semi sphere is 50mm
 Nov 15th 2017, 06:21 AM #5 Senior Member     Join Date: Jun 2016 Location: England Posts: 366 There is a standard equation for calculating the volume of a sphere: 4/3 PI R^3 Where PI =3.13159... R is the Radius of the Sphere (half the diameter) you want the volume of a semi-sphere, which is half the above: 2/3 PI R^3 I am assuming the Height of your semi-sphere (5cm) is the radius (note conversion from millimetres to centimetres, just makes the numbers smaller and easer to deal with). thus: 2/3 PI * 5^3 = 2.0944 * 125 = 261.8 cubic centimetres (note that I have rounded some of these numbers off a little). 1 litre is 1000 cubic centimetres thus the volume of your semi-sphere is 0.2618 litres (or just over 1/4 litre) assuming that oz93666 has given the correct value for the density of chocolate and that his units are kilograms per litre then you will need 1.056 *0.2618 = 0.276 kg (276 grams) of chocolate. __________________ ~\o/~

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