A Reuters poll showed China's economy likely grew at its weakest pace in more than five years in the third quarter as a property downturn weighed on demand, raising the chances of more aggressive policy steps that may include cutting interest rates.br The economy may have expanded 7.3 percent in the third quarter from a year earlier - the weakest reading since the first quarter of 2009, when growth hit 6.6 percent during the height of the global crisis, according to a poll of 20 economists.