Problem
Select an expression to calculate $d$ for any star. $d=\tan (\theta)$ $d=\frac{1}{\operatorname{san}(\theta)}$ $d=\sin (\theta)$ $d=\frac{1}{\sin (\theta)}$
Solution
Step 1 ：Analyze the given expressions to find the correct one for calculating the distance $d$ for any star using the angle $\theta$.
Step 2 ：The correct expression is $d = \sin(\theta)$. \[ \boxed{d = \sin(\theta)} \]
