l=2πR, p=½(a+b+c), S=pR, R=(abc)/(4√(p(p-a)(p-b)(p-c))
p= ½(4+13+15)=16
R= (4*13*25)/(4√(16*(16-4)*(16-13)*(16-15))=
=780/(4√(16*12*3*1)=780/4√576=
=780/96=8.125
l=2π*8.125=2*3.14*8.125=51.025
32/5 : x = 64/5 : 4/3
32/5 : x = 48/5
X= 32/5 : 48/5
X= 2/3
7975 = 5*5*11*29
2285 = 5*457
<span>НОД(7975, 2285) = 5</span>
1+1/3=1 целая 1/3
1 целая 1/3 *3 =4/3*3=4
Ответ:4