Answer:
SA = 112 cm²
Steps:
to solve this problem we have to calculate the surface area of the whole block and let be SA
first the surface area of the square pyramid:
the area of one triangle = (height × base)/2
given:
height = 6 cm
base = 4 cm
A = (6×4)/2
A = 24/2
A = 12 cm²
since it's a square triangle
then the surface area of the pyramid excluding the base:
Ap = A × 4
Ap = 12 × 4
Ap = 48 cm²
now the inferior part which is a rectangular prisme
Ar = 4(height×lenght)+lenght²
Ar = 4(3×4)+4²
Ar = 4×12+16
Ar = 48+16
Ar = 64 cm²
and now we can calculate the surface area of the whole block
SA = Ap + Ar
SA = 48 + 64
SA = 112 cm²