millimetre (mm) – 0.001 m; centimetre (cm) – 0.01 m; decimetre (dm) – 0.1 m; metre (m) – 1 m; decametre (dam) – 10 m; hectometre (hm) – 100 m; kilometre (km) – 1,000 m; megametre (Mm) – 1,000,000 m; gigametre (Gm) – 1 x 10 +9 m; terametre (Tm) – 1 x 10 +12 m; petametre (Pm) – 1 x 10 +15 m; exametre (Em) – 1 x 10 +18 m 1 dm 2 = 10000 mm 2. square decimeter . dm 2. square millimeter . 10000 mm 2. Conversion base : 1 dm 2 = 10000 mm 2. Conversion base : 1 mm 2 = 0.0001 dm 2. Switch eKhx5w.