Find Sin, Cos, Tan from Lengths of Triangle Sides

Ally and Xavier were trying to guess each other's height. Ally told Xavier she could make a pretty accurate estimate of his height without measuring him but by measuring an angle and the distance between him and a chosen point on the ground. Xavier didn't believe Ally but said she could try it.

What Xavier didn't know is that Ally has learned all about using trigonometry to find distances.

Ally measured the distance between Xavier's feet and the point she chose on the ground, the distance was $6$ feet. She then measured the angle of elevation from the point on the ground to Xavier's head. That angle was $45^{\circ}$.