A paragraph could very well be one sentence, but it could just as easily be a long 20 sentence paragraph. It's usually thought of as being a complete separate thought and containing as many sentences are needed before you reach a natural breaking point to move on to the next paragraph. Hope that helped.
Centi-means one-hundredth, so 1metre = 100 centimeters, therefore 1 decameter = 10 x (100 centimeters) = 1000 centimeters. Hecto-means one hundred, therefore 1 hectometer = 100 meters = 10 decameters. Kilo-means one thousand, of course, so 1 kilometer = 1000 meters, and since 1 hectometer = 100 meters, 1 kilometer = 10 hectometers.
0.001 kilometers = 0.01 hectameters = 0.1 decameters = 1 meters = 10 decimeters = 100 centimeters = 1000 millimeters This means that 1 Decameter equals .01 Kilometer and .1 hectometers and 10 meter and 100 decimeters and 1000 centimeter and 10000 millimeters.