Anonymous 1)run the 100 metres... 2) jump 3 metres...why do we use article in fist sentence?

It depends on the sentence. Sometimes the definite article is used, and sometimes not.

Run the hundred meters to the end of the block. (The distance to the end of the block is 100 meters. It refers to something very specific.)

If you can run 100 mete

If I run 100 meters I am referring to the distance I ran. If I 'ran the 100 meters' I am referring to the race in which I took part. At a track meet I would 'run the 100 meters', meaning I entered the race whose length is 100 meters, which is to say I ran a specific race and not just any generic 100 meters. It is more correct to say something like 'I ran the 100-meter race' but 'I ran the 100

thank you so much