Explanation:
by using pythagorean theorem:
XW²+XY²=
(2×6.4)² + 9.6² =
12.8²+9.6²=
163.84 + 92.16= 256
WY²= 16²= 256
so, XW²+XY²=WY²
=> the WXY is a right triangle, and X is a right angle.
so XY is perpendicular to XW as the diameter of circle Z.
and XY is tangent to circle Z