Geometry problem

Find the circumradius.

Hello Guest!

Cosine law:

$cos(\alpha)=\dfrac{b^2+c^2-a^2}{2bc}=\dfrac{2\cdot 25^2-20^2}{2\cdot 25\cdot 25}=0,68\\ \alpha=acos(0,68)=47.156°\\ \color{blue}\frac{\alpha}{2}=23.578°$

$cos(\frac{\alpha}{2})=\dfrac{\frac{25}{2}}{r}\\ r=\dfrac{12.5}{cos(23.578°)}=13.639$

$The\ circumradius\ is\ \color{blue}r=13.639$.

  !