Кольцо ограничено двумя окружностями, радиусы которых равны 3 см и 5 см (рис. 8.18). Чему равна площадь этого кольца?

Dear ...,
Thank  you for your letter.
I want to tell you about my flat.
 I like my house.There are four rooms: Dining room,3 Bedroom.There is a bathroom and a kitchen too! My favorite Bedroom is modern.There is a bed, a window overlooking the playgroun and two chairs with desk. 

Write back soon.
Love,
Alex