Gdz Po — Geometrie Skachat Besplatno Atanasjan

Atanasyan is likely a reference to Lev Atanasyan, a Russian mathematician and educator known for his work in geometry and his authorship of textbooks on the subject. The textbook you're referring to is probably "Геометрия, 7-9 классы" (Geometry, 7-9 classes) by L.S. Atanasyan and others.