Aloha :)
Pythagoras: \(w^2=u^2+v^2=84^2+68^2=11680\implies w=\sqrt{11680}\approx108,07\)
$$\tan\alpha=\frac{u}{v}=\frac{84}{68}\implies \alpha=\arctan\left(\frac{84}{68}\right)\approx51,01^\circ$$
$$\alpha+\beta=90^\circ\implies\beta=90^\circ-51,01^\circ=38,99^\circ$$
$$F=w\cdot\frac{h}{2}\implies \frac{u\cdot v}{2}=\frac{w\cdot h}{2}\implies h=\frac{u\cdot v}{w}=\frac{84\cdot68}{108,07}=52,84$$