Check the picture below.
Make sure your calculator is in Degree mode.
since we know what TQ is, let's use it on the blue triangle.
[tex]sin(45^o)=\cfrac{\stackrel{opposite}{h}}{\underset{hypotenuse}{TQ}}\implies TQsin(45^o)=h\implies 4.565\approx h[/tex]
notice, I didn't use the 6.455 instead I used TQ, for namely the expression, to avoid any rounding issues.
