"Hans skridt er to meter lange."
Translation:His steps are two meters long.
'His stride is two metres long' seems like the most natural way to say this to me.
So skridt is plural. Does a singular for skridt exist in Danish?
The singular is also "skridt". Had the singular version been used here the only difference would have been in the last word. I.e. "Hans skridt er to meter langt". And it might be worth noting that "skridt" also means "crotch" which gives the singular version a potential, albeit slightly nonsensical, double meaning.
"His pace is two metres long" is how we say it in the U.K., but rejected by Duo. Meters is from U.S.A., and metres is U.K. A meter in the U.K. is a measuring device. When we talk about the length of our step, we say the length of our pace. Have reported.