What is the surface area of a square pyramid with a height of 12 mm and a base that measures 8 mm on each side?

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

341

step-by-step explanation:

all you have to do is 9x31 (which equals 279) and then 20x31 (which equals 620). then you have to subtract. 620-279=341.