Proportion

Proportion

1. ·

   • Means y and x are directly proportional
     • Whatever you do to x you must do to y
       • Formula - y = kx
         • k = constant of proportionality
         • Can change formula slightly for if x is cube,squared, etc...
           • y = kx²
     • Or can say varies directly

2. Direct Proportion example

   • The volume of a hot air balloon is proportional to the cube of it's height. A balloon of height 5m has a volume of 240m³ 1)Find the volume of the balloon of height of 10m. 2) Find the height of a balloon of volume 100m³

3. Inverse proportion

   • Whatever you do to one, you do opposite to other
   • Formula - y = k/x
     • y varies inversely as x
   • Example
     • The number of letters that will fit on aline is inversely proportional to the font size. At font size 12. 66 letters will fit onto a line. 1) How many letters will fit on a line at font size 14

4. Tips

   • Do lots of practice questions

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