Answer: 33
Step-by-step explanation:
The base is a 3 by 3 square of area 3*3 = 9 sq ft.
Each of the lateral faces is a triangle with base = 3 and height = 4. The area of one triangle is base*height/2 = 3*4/2 = 12/2 = 6 sq ft. Four such triangles combine to a lateral surface area of 6*4 = 24 sq ft.
Overall, the entire figure has a surface area of 9+24 = 33 square feet