Answer:
266.39mm²
Step-by-step explanation:
The formula for surface area of a square based pyramid =
S.A = a² + 2a √a²/4 + h²
Where
a = base length = 8mm
s = Height of the pyramid = 12mm
Hence,
S.A = 8² + 2 × 8 × √8²/4 + 12²
S.A = 64 + 16 ×√64/4 + 144
S.A = 80 × √16 + 144
S.A = 80 × √160
S.A = 266.39 mm²
Therefore, the surface area of a square pyramid is 266.39 mm²
