check the picture below.
so the pyramid looks more or less like so, notice, each triangular face has a base of 1, and a height of 1.
the total surface area of the pyramid is just, the area of all four triangular faces plus the area of its squarish base.
[tex]\bf \stackrel{\textit{squarish base's area}}{(1\cdot 1)}~~~~+~~~~\stackrel{\textit{triangular faces' area}}{4\left[ \frac{1}{2}(1)(1) \right]}[/tex]
