C=2pir, so take half of 15 which is 7.5 and plug it in as r and you get 47.12. Or just look up circumference calculator on google.
The key is to find the first term a(1) and the difference d.
in an arithmetic sequence, the nth term is the first term +(n-1)d
the firs three terms: a(1), a(1)+d, a(1)+2d
the next three terms: a(1)+3d, a(1)+4d, a(1)+5d,
a(1) + a(1)+d +a(1)+2d=108
a(1)+3d + a(1)+4d + a(1)+5d=183
subtract the first equation from the second equation: 9d=75, d=75/9=25/3
Plug d=25/3 in the first equation to find a(1): a(1)=83/3
the 11th term is: a(1)+(25/3)(11-1)=83/3 +250/3=111
Please double check my calculation. <span />
28 + 18 - pai, <span>atualmente
28+18+18= 64 -soma
64</span>