Use a model for body surface area, BSA, such that $B S A=\sqrt{\frac{w h}{3600}}$, where $w=$ weight in $\mathrm{kg}$ and $h=$ height in $\mathrm{cm}$. Find the weight of a $175-\mathrm{cm}$ male to the nearest $\mathrm{kg}$ whose $B S A=2.1$.

Step 1 ：We are given a model for body surface area (BSA) such that \(BSA = \sqrt{\frac{w \times h}{3600}}\), where \(w\) is the weight in kg and \(h\) is the height in cm.

Step 2 ：We are asked to find the weight of a 175 cm male whose BSA is 2.1. We can rearrange the formula to solve for weight. The rearranged formula would be \(w = \frac{BSA^2 \times 3600}{h}\).

Step 3 ：Substitute the given values into the formula to find the weight. Where BSA = 2.1 and h = 175.

Step 4 ：By substituting the values into the formula, we get \(w = \frac{(2.1)^2 \times 3600}{175}\).

Step 5 ：Solving the above expression, we find that \(w \approx 91\).

Step 6 ：Final Answer: The weight of a 175-cm male whose BSA is 2.1 is approximately \(\boxed{91}\) kg.