Mark the radius onto your pool tile with a radius gauge and a marker. Use a marker that contrasts with the color of the tile so you can easily see it.
Place the tile onto the table of a band saw. Cut a straight line from the edge of the tile to the line you scribed on the tile that marks the radius. Repeat this every 1 inch across the length of the tile. Be careful not to pass the line you scribed; otherwise, you are cutting into the portion of tile you plan to keep.
Cut along the line you scribed on the tile with the band saw blade. As you reach each "relief" cut, a section of unwanted tile will come off. This allows the back of the blade to stay straight and reduces unwanted heat buildup that could cause the tile to break. Stay as close to the line as possible to ensure a consistent cut.