Answer: Triangle has three sides, which are:
[tex]\begin{gathered} O=500\operatorname{cm} \\ P=600\operatorname{cm} \\ Q=380\operatorname{cm} \\ \end{gathered}[/tex]We need to find the angle p, that is right across the side P:
[tex]\angle A=\arccos (\frac{b^2+c^2+a^2}{2bc})=0.97895\text{rad}=56.09\text{degres}[/tex]This is the value of angle A