Holy Moley! Is this the standard for P6 nowadays? Crap no wonder tuition business is booming.
This is definitely not the typical way of solving perimeter questions (which is to find the length and the breath). Have to approach it in a different manner. Pardon my atrocious drawing skills.
Total 488 square tiles
Minus away the 4 corners of 16 tiles each will give a remaining 424 square tiles
These 424 square tiles will be alongside of the pool perimeter.
However, they are laid 4 aside, meaning that there will be 106 groups of 4 tiles
This means that 106 tiles will be lining the perimeter of the pool.
Therefore, perimeter of pool = 106 x 0.25 = 26.5m