1. Calculate the perimeter of the base
2. Multiply half of the perimeter of base with the slant height
So ,
Perimeter of base = 60m+60m+60m+60m = 240m
Lateral area of pyramid =
[tex] \frac{1}{2} \times (240m) = 120m \\ \\ 120m \times 40m = 4800m[/tex]
