250 dam = 250 * 10^3 cm = 250 000 cm
0,8924 km = 0,8924 * 10^5 cm = 89240 cm
(403,7 cm)^2 = 162973,69 cm^2 = 162973,69 * 10^(-4) m^2 = 16,297369 m^2
(345 cm)^2 = 119025 cm^2 = 119025 * 10^(-4) m^2 = 11,9025 m^2
(0,00234 km)^3 = (2,34m) ^3 = 12,812904 m^3