Answer:
645 m²
Explanation:
This figure has four similar sloping sides, each of which is a triangle with base 15 m and height 14 m.
The formula for the area of a triangle of base b and height h is A = (1/2)(base)(height).
In this case, the area of each of the four triangles is
A = (1/2)(15 m)(14 m) = 105 m².
Since there are four such triangles, the total area of the triangular sides is 4(105 m²) = 420 m².
The area of the base is A = (15 m)² = 225 m²
Combining side area with base area, we get a total surface area of
A = 225 m² + 420 m² = 645 m²
Please note: I am not familiar with the "net" you mention. If you want a problem solved in a particular way, and can share the necessary tool or tools, please do so.