Answer:
[tex]\large\boxed{S.A.'=9b^2+\dfrac{6}{5}bh}[/tex]
Step-by-step explanation:
The formula of a surface area of a square pyramid:
[tex]S.A.=b^2+2bh[/tex]
b - side of the square
h - slant height
The new lenghts:
[tex]3b[/tex] - side of the square
[tex]\dfrac{h}{5}[/tex] - slant height
Substitute:
[tex]S.A.'=(3b)^2+2(3b)\left(\dfrac{h}{5}\right)=9b^2+\dfrac{6}{5}bh[/tex]
