Step-by-step explanation:
With no photo of the design is imposible to calculate exactly the design area. However:
We know that the area of a square is:
where L is the leght of the square's side
Also, the area a triangle is:
where h is the height and b is the base (see the figure)
So, the total area, assuming that all square tiles are equal between them (the same for the triangular ones):
