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.
There are 100 centimeters in a meter (think 100 cents in a dollar), so there are 400 centimeters in 4 meters. What is 6.1 meters in feet? 6.1 metres is equal to 20.0131234 feet.