Math Is Fun Forum

Monique

Member

Registered: 2007-02-17

Posts: 22

lost in the abyss of motherhood!!!

More help requested

An algebraic model for the hieght of women based on their weight is described by a formula. The formula states, to find the hieght of a women in cm, multiply her weight in kg by 2.1 and then add 40.

a)  write this formula and define any varibales that you have used?

b)  Use your formula to predict the hieghts of the women missing in the floowing table:

    weight kg     height cm
      57                 159.7
      59                  163.9
     61
     69

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,422

Re: lost in the abyss of motherhood!!!

The formula would be

where h is the height in centimetres, and w the weight in kilograms.

The height in centimetres when weight is 61 kiloghrams is (2.1x61)+40= 168.1 centimetres.

Similarly, when the weight is 69 kilograms, the height is (2.1x69)+40= 184.9 centimetres.

The data given for the first case is weight is 57 kilograms. As per the formula, the height would be (2.1x57)+40= 159.7 centimetres, which is the height given. The formula has been tested for correctness!

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Monique

Member

Registered: 2007-02-17

Posts: 22

Re: lost in the abyss of motherhood!!!

you're an absolute genius, ganesh! Thanks

so if I wanted to go about rearanging the formula in order to make weight the subject, how would I do that?

MathsIsFun

Administrator

Registered: 2005-01-21

Posts: 7,713

Re: lost in the abyss of motherhood!!!

Start: h = 2.1w + 40
Subtract 40 from both sides: h-40 = 2.1w
Divide both sides by 2.1: (h-40)/2.1 = w

Answer: w = (h-40)/2.1

Try h= 159.7: w = ( 159.7-40)/2.1 = 57

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"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman