[tex]A = \frac{5}{2}t^{2} \sqrt{5 + 2 \sqrt{5} } [/tex]
[tex]A = \frac{5}{2} (4)^{2} \sqrt{5 + 2(2.236067978)} } [/tex]
[tex]A = \frac{5}{2} (16) \sqrt{5 + 4.472135956} [/tex]
[tex]A = 40 \sqrt{9.472135956} [/tex]
[tex]A = 40(3.077683537)[/tex]
[tex]A = 123.1073415cm^{2} [/tex]
