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Formulas for square pyramid:
SA=a^2+2a \sqrt{ \frac{a^2}{4}+h^2 }  \\ V=a^2* \frac{h}{3}
a means the base edge and h means height or altitude.

SA=10^2+20 \sqrt{ \frac{10^2}{4} +9^2}  \\ =100+20 \sqrt{25+81}  \\ =100+20 \sqrt{106}cm^2

V=a^2* \frac{h}{3}=10^2* \frac{9}{3}  =100*3=300cm^3