tolong yaa sama caranya :)

V= πr²t
16956= 3,14 x r² x 6
16956= 18,84 x r²
r²= 16956/18,84= 900
r= √900= 30

K= 2πr= 2 x 3,14 x 30= 188,4

Maaf jika salah. :)