hi dont know were to put this this is for an assignment and i nee help pritty quick
a)$\displaystyle F=\frac{95}{1.7^2}$ (calculate it yourself in which category it lies)
b)$\displaystyle h=\sqrt{\frac{W}{F}}$
c)$\displaystyle h>\sqrt{\frac{65}{25}}$m
For remaining questions you should try it yourself and ask if you get stuck anywhere.
to #4 a): You only have to plug in the given values to calculate F:
$\displaystyle F = \dfrac{95\ kg}{(1.7\ m)^2} = 32.87\ \dfrac{kg}{m^2}$
So this person obviously(!) has crossed the border
b)
$\displaystyle F = \dfrac{w}{h^2}~\implies~h^2=\dfrac wF~\implies~h=\sqrt{\dfrac wF}$
c) Plug in the given values and use the property of being healthy:
$\displaystyle \dfrac{65}{h^2} < 25~\implies~\dfrac{65}{25} < h^2~\implies~h>\sqrt{\dfrac{13}5}\approx 1.61\ m$