Learn Finnish: Maanmittari seisoo kymmenen metrin päässä tontin rajasta. - The land surveyor stands ten meters away from the plot's boundary.

This is the classic structure for expressing static distance. The distance itself goes into the genitive case (kymmenen metrin), followed by the postposition päässä. We use päässä (rather than päästä) because the surveyor is stationary (seisoo).

Since numbers usually require the partitive case (like kymmenen metriä), why is it kymmenen metrin here?

When a number phrase acts as the subject or object, it takes the partitive. However, postpositions like päässä require the word or words in front of them to be in the genitive. Therefore, both the number and the noun must snap into the genitive: kymmenen (genitive of kymmenen) and metrin (genitive of metri).

Why is the word for boundary in the elative case (rajasta)?

When expressing distance from a reference point using the postposition päässä, Finnish requires the elative case (-sta or -stä) for that reference point. So, from the boundary translates to rajasta, indicating exactly where the ten-meter gap starts.

What makes up the compound word maanmittari?