Answer:
S.A. = 297 cm²
Step-by-step explanation:
We have a square with a side a = 9 cm and four congruent triangles with a base b = 9 cm and a height h = 12 cm.
The formula of an area of a square:
[tex]A_S=a^2[/tex]
Substitute:
[tex]A_S=9^2=81\ cm^2[/tex]
The formula of an area of a triangle:
[tex]A_T=\dfrac{bh}{2}[/tex]
Substitute:
[tex]A_T=\dfrac{(9)(12)}{2}=(9)(6)=54\ cm^2[/tex]
The Surface Area of the square pyramid:
[tex]S.A.=A_S+4A_T[/tex]
Substitute:
[tex]S.A.=81+4(54)=81+216=297\ cm^2[/tex]
