Solving for the lateral surface of the square pyramid, we need to use the formula shown below:
Lateral Area = a √ (a² + 4h²) where "a" for the base edge and "h" for the height
We have given values such as:
Base = 12 inches
Height = 15 inches
Lateral area = 12 √ (12² + 4*15)
Lateral area = 171.39 inches²
The answer is 171.39 inches².