It depends on what you want to convert it to. A cm is 2/5 of an inch for example.
Here are the specs from Apple's website: Height: 9.56 inches (242.8 mm) Width: 7.47 inches (189.7 mm) Depth: 0.5 inch (13.4 mm) Weight: 1.5 pounds (.68 kg) Wi-Fi model; 1.6 pounds (.73 kg) Wi-Fi + 3G...
1.1 cm by 1.8 cm is 1.1 cm x 1.8 cm = 1.98 cm2
There isn't another size of iPad yet but if you mean the 64gb version then its still called an iPad
2.3 x 1.8 = 4.14 cm2 (4.14 square centimetres)