$\begin{array}{l}y=r \sin \theta \\ y=6 \sin 90\end{array}$

Step 1 ：Convert 90 degrees to radians: \(\theta = \frac{90 \times \pi}{180} = \frac{\pi}{2}\)

Step 2 ：Calculate y: \(y = 6 \times \sin(\frac{\pi}{2}) = 6\)

Step 3 ：\(\boxed{y = 6}\)