Multiply the length and the width of the rectangles together to get the square footage.
Tiling a wall that is not square.
When you get to the corners you will need to do the cutting free hand since the corner is not square any miter gage or sliding feature on the saw will not line up correctly.
With the uneven ceiling level you would normally level or laser a horizontal line that runs around the shower enclosure at the top of the tile if leaving a top border tile free see below then measure your row lines down from there to the bottom and start with any bottom trip and cuts and actually place the tile from bottom up to the top.
However some tile layers will actually lay the top row first then work down from there to the bottom easier to get eye level rows perfectly level.
If you have a curved or angled wall you need to act as if the curve or angle were not there and pretend that it is a rectangle.
The general rule for laying tile is to start from the center of the area that you are going to be tiling.
The last thing i want are little angled tile pieces running along that side.
You will then want to add approximately 10 percent to that number so that you can have enough for waste.
How to install luxury vinyl tiles in a room where the wall is not straight duration.
Laying tile and the wall is not square.
Lippage can be eliminated on most walls by hanging new drywall or backerboard before tiling.