Question 453159
Let's mark length, width and height of the model with l, w and h.
Let's mark length, width and height of the actual building with L, W and H.
:
01. If each centimeter on the model represents 2.5 meters on the actual building
then height of 225 centimeters on the model is
:
    H = h*2.5= 225*2.5 = 562.5 meters - very tall building :-) 
:
02. This model/building is prism with the rectangle for the base so its volume is
:
    V = L*W*H
:
    L = l*2.5 = 50*2.5 = 125 meters
    W = w*2.5 = 38*2.5 = 70 meters
:
    V = L*W*H = 125*70*562.5 = 4921875 cubic meters
:
03. Surface area of the building is the sum of areas for all sides:
:
    B  - 2 bases are ceiling and floor
    L1 - 2 lateral sides of the prism with length and height
    L2 - 2 lateral sides of the prism with width and height
:
    A = 2B+2L1+2L2
    A = 2WL+2WH+2LH
    A = 2*70*125 + 2*125*562.5 + 2*70*562.5
    A = 236875 square meters