we calculate the area of each figure and add to the end
Triangles
the area of a triangle is
[tex]A=\frac{b\times h}{2}[/tex]
replacing
[tex]\begin{gathered} A=\frac{6.8\times6.4}{2} \\ \\ A=21.76 \end{gathered}[/tex]
the area of alla triangles is 21.76 square centimeter
Square
the area of the square is
[tex]\begin{gathered} A=l\times l \\ A=6.8\times6.8 \\ A=46.24 \end{gathered}[/tex]
the ara of the square is 46.24 square centimeter
Total area
we add the area of each figure that makes up the pyramid(4 triagles and 1 square)
[tex]\begin{gathered} A=21.76+21.76+21.76+21.76+46.24 \\ A=133.28 \end{gathered}[/tex]
Total area is 133.28 square centimeters
