In this regular pyramid find the area of http://alt1.mathlinks.ro/latexrender...3585b165f6.gif

i think that we have to solve this by using similar triangles and than continue with other things , and we have to solve it in terms of $\displaystyle a$ and angle http://alt2.mathlinks.ro/latexrender...80b4948e68.gif and http://alt1.mathlinks.ro/latexrender...8632e2f8c4.gif.

I'm having problems with this.

Please help!