Answer
$65.3\ cm $
Work Step by Step
The relationship of two rotating pulleys connected by a belt is:
(diameter of A)(rpm of A) = (diameter of B)(rpm of B).
Now, we have
$$
98\times 240=x\times 360\Longrightarrow x=\frac{98\times 240 }{360}=65.33\ cm\approx 65.3\ cm .$$
