Use the cosine rule in a non-right-angled triangle

Triangle \(XYZ\) is a non-right-angled triangle

Side \(x\) is opposite angle \(X\) and is unknown. Side \(y\) is opposite angle \(Y\) and is 8 m. Side \(z\) is opposite angle \(Z\) and is 8 m

Sides \(y\) and \(z\) meet at vertex \(X\). The included angle between them is \(X=55^{\circ}\). Find side \(x\)