\(\displaystyle \text{Given: }\:AP\!B\text{ is tangent to circle }O\text{ at }P,\;X\!Y \parallel AP\!B\)
\(\displaystyle \text{Prove that }\Delta P\!XY\text{ is isosceles.}\)
Code:P A - - - * o * - - - B * / \ * * / \ * * / \ * / \ * / \ * * / \ * * / \ * / \ X o- - - - - - - - -o Y * * * * * * *