well, the pyramid has a square for its base, a 0.4x0.4 square, and it has 4 triangular faces, each of which has a base of 0.4 and a height/altitude of 5.
notice, the slant-height of the pyramid is just the altitude of a triangular face.
so we can just get the area of the base and the triangular faces, sum them up, and that's the area of the pyramid.
[tex] \bf \stackrel{base}{(0.4\cdot 0.4)}~~+~~\stackrel{4~triangular~faces}{4\left[ \cfrac{1}{2}(0.4)(5) \right]}\implies 0.16~~+~~4\implies 4.16 [/tex]
