The answer is 129.13 is your answer. Remember, the perimeter of the base is 4s since it is a square. There is no formula for a surface area of a non-regular pyramid since slant height is not defined. To find the area, find the area of each face and the area of the base and add them.
Total surface area of pyramid = area of base + area of 4 triangular faces
area of base = 6.4*6.4 = 40.96 cm²
area of one triangular face = 1/2 * 6.4 * 6.1 = 19.52 cm²
Surface area of pyramid = 40.96 + 4 * 19.52 = 119.04 cm²
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Mathematics, published 11.05.2023
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