Решитьнужно поставить что-то в пасив что-то в актив. ​

видимо, речь идет о правильном шестиугольнике. у него сторона = r описанной окружности.  площадь круга = пиr^2. 

если соединим концы указанной диагонали с центром окружности, то получим сектор, площадь которого s1 = 1/3 площади круга. если от нее отбросить площадь треугольника, образованного двумя радиусами и указанной диагональю, то получим искомую площадь s. 

площадь треугольника s2 = 1/2 r*r*sin угла между радиусами = r^2/2 * sin120 = r^2*кв.корень(3)/4.  s = s1 - s2 =

my foreign   friend.

“a friend who is far away is sometimes much nearer than one who is at hand.”~ gibran khalil gibran ~ i make friends easily so i have a lot of foreign   friend. but the best of all is only one. he is from chine. his name is dean. he was born in guangdong. he is fifteen. my friend is very friendly, good – natured, sociable, kind, he is always smiling and laughing, he never loses his temper and he always keeps his word.

we have known each other for   two years. he speak english well, so i communicate with  dean on the skype  almost every day.  when i  am needing get a  support  he  always gives me kindly advice.   dean have  interests as the same as i have. we can have some real talks , share some real feelings , discuss some life plans , dreams , studying  problems ,  secret happiness  or sorrow i think, nowadays it is very important to have  foreign friends,  because you are learning many interesting facts about people from  the another country about their traditions, habits and customs. 

“a friend who is far away is sometimes much nearer than one who is at hand.”~ gibran khalil gibran ~ i make friends easily so i have a lot of foreign friend. but the best of all is only one. he is from chine. his name is dean. he was born in guangdong. he is fifteen. we have known each other for  two years.he speak english well, so i communicate with  dean on the skype  almost every day.  when i  am needing get a  support  he  always gives me kindly advice.  dean have  interests as the same as i have. we can have some real talks , share some real feelings , discuss some life plans , dreams , studying  problems ,  secret happiness  or sorrow my friend is very friendly, good – natured, sociable, kind, he is always smiling and laughing, he never loses his temper and he always keeps his word. i think, nowadays it is very important to have  foreign friends,  because you are learning many interesting facts about people from  the another country about their traditions, habits and customs.