5) AB =BC =CD =DA ; p=16√3 ; <A =60° .-------------------------------------------------------C =2π*r ==>?4a =16√3 ;a =4√3 ;h =a*sin<A ;r =1/2*h =1/2*4√3*cos60° =2√3*√3/2 =3.C =2π*3 =6π.ответ: 6π.********************************************6) AD -AB =7; S =AD*AB =120.--------------------------------------------C - ?C =2π*R =π*AC =π√(AB² +AD²).{AD -AB =7; AD*AB =120.⇔{AD =AB +7 ; (AB +7)*AB =120.************************* * * * * AD =x ;AB =y ⇔ {x - y =7 ; xy =120. * * * * ************************ AB² +7AB -120 =0 ; * * * * * квадратное уравнение * * * * *AB =8 *** AB = -15 не решение ***AD =AB+7 =8+7=15 .-------С =π√(8² +15²) =π√289 =17π .ответ: 17π .