mohon bantuannya ya :)

Putaran = keliling
Keliling =
[tex]k = (\frac{3}{4} \times 2 \times \pi \times r \:) +2 r \\ = \frac{3}{4} \times 2 \times 3.14 \times 50 +( 100) \\ = 235.5 + 100 \\ = 335.5[/tex]
karena 4 kali putaran, maka 335.5 × 4
= 1342 cm atau 13,42 m (A)