Utilisateur:Louperivois/brouillons

$S={\frac {p\cdot a}{2}}$ $S={\frac {25\cdot 6}{2}}$ $S={\frac {25\cdot 6}{2}}$ $S={\frac {150}{2}}$ $S=75~$

${\begin{matrix}S&=&{\frac {5a^{2}}{4}}\cot {\frac {\pi }{5}}\\\ S&=&{\frac {125}{4}}\cot 0,6283185307\\\ S&=&31,25\cdot 1,3763819204\\\ S&=&43,0119350147\end{matrix}}$

${\begin{matrix}S&=&{\frac {a^{2}}{4}}{\sqrt {25+10{\sqrt {5}}}}\\\ S&=&6,25{\sqrt {47,3606797750}}\\\ S&=&6,25\cdot 6,8819096023\\\ S&=&43,0119350147\end{matrix}}$

${\begin{matrix}S_{t}&=&2(11,8882064538)+\left({\frac {2x\cdot h}{2}}\right)\\\ S_{t}&=&23,7764129076+\left({\frac {5\cdot 7,6942088429}{2}}\right)\\\ S_{t}&=&23,7764129076+19,2355221073\\\ S_{t}&=&43.0119350148\end{matrix}}$

${\begin{matrix}e^{2}&=&x^{2}+h^{2}\\\ 8,0901699437^{2}&=&2,5^{2}+h^{2}\\\ 65,4508497187&=&6,25+h^{2}\\\ {\sqrt {59,2008497187}}&=&{\sqrt {h^{2}}}\\\ 7,6942088429&=&h\end{matrix}}$

${\begin{matrix}S_{t}&=&{\sqrt {p(p-b)(p-c)(p-e)}}\\\ S_{t}&=&{\sqrt {9,0450849719(9,0450849719-5)(9,0450849719-5)(9,0450849719-8,0901699437)}}\\\ S_{t}&=&{\sqrt {9,0450849719\cdot 4,0450849719\cdot 4,0450849719\cdot 0,9549150281)}}\\\ S_{t}&=&{\sqrt {141,3294526877}}\\\ S_{t}&=&11,8882064538\end{matrix}}$

$p={\frac {8,0901699437+5+5}{2}}$ $p={\frac {18,0901699437+5+5}{2}}$ $p=9,0450849719~$

${\begin{matrix}e^{2}&=&b^{2}+c^{2}-2ab\cos {\gamma }\\\ e^{2}&=&5^{2}+5^{2}-2\cdot 5\cdot 5\cdot \cos {108}\\\ e^{2}&=&50-50\cdot -0,3090169944\\\ e^{2}&=&50--15,4508497187\\\ {\sqrt {e^{2}}}&=&{\sqrt {65,4508497187}}\\\ e&=&8,0901699437\end{matrix}}$