# How do I find the BMI of a person's weight by a variation formula?

Asked by chelle21689 (7719) October 31st, 2010

I know that direct variation is y=kx, inverse variation is y=k/x, and joint variation is y=kxz

I’m having issues setting up this problem because it uses the words “inverse” and “direct”.

“BMI is used by physicians to assess a person’s level of fatness. BMI varies directly as an individual’s weight in pounds and inversley as the square of the individual’s height in inches. A person who weights 118 pounds and is 64 inches tall has a BMI of 20. (BMI rounded to nearest whole number). Find the BMI of a person who weighs 165 pounds and is 72 inches tall.”

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It’s not a linear equation. It’s BMI = M/h^2 where M is Mass in kg, and h is height in meters.

I’ll leave it to you to work out the constants of the English system.

LuckyGuy (39600)

Thanks, I’ll try it.

chelle21689 (7719)

It’s actually BMI=K(weight/height^2)

chelle21689 (7719)

or