Question

what's the surface area of this shape?

Answer 1

Surface Area of the square = 8 x 8 = 64 cm²

Surface Area of the 4 triangle = 4 x [ 1/2 x 8 x 14] 
Surface Area of the 4 triangle = 4 x [ 56] 
Surface Area of the 4 triangle = 224 cm²

Total Surface Area = 64 + 224 = 288 cm²

Answer:  288 cm²