Step 1 :The surface area of a pyramid is given by the formula: \(\text{Surface Area} = \text{Base Area} + \frac{1}{2} \times \text{Perimeter of Base} \times \text{Slant Height}\)
Step 2 :Here, the base is a square with side length 9 cm, so the base area is \(9 \times 9 = 81 \, \text{cm}^2\).
Step 3 :The perimeter of the base is \(4 \times 9 = 36 \, \text{cm}\).
Step 4 :The slant height is given as 12 cm.
Step 5 :Substituting these values into the formula, we get: \(\text{Surface Area} = 81 \, \text{cm}^2 + \frac{1}{2} \times 36 \, \text{cm} \times 12 \, \text{cm} = 81 \, \text{cm}^2 + 216 \, \text{cm}^2 = 297 \, \text{cm}^2\).
Step 6 :\(\boxed{\text{So, the surface area of the pyramid is 297 cm}^2}\)