Hey if you have a triangle with one side 25. another side 25. and the bottom side 30. You just use law of cosines to figure out the answer to finding an angle with the triangle?
$\displaystyle a^{2}=b^{2}+c^{2}-2bc\cos A$
$\displaystyle \cos A=\frac{b^{2}+c^{2}-a^{2}}{2bc}$
$\displaystyle b^{2}=a^{\text{2}}+c^{2}-2ac\cos B$
$\displaystyle \cos B=\frac{a^{2}+c^{2}-b^{2}}{2ac}$
$\displaystyle c^{2}=a^{2}+b^{2}-2ab\cos C$
$\displaystyle \cos C=\frac{a^{2}+b^{2}-c^{2}}{2ab}$