尺子 (chǐ zi): ruler

In math class, the teacher asked us to use a ruler to measure the length and width of the textbook.

One side of this table is a bit slanted. I compared it with a ruler and found it was two centimeters shorter than the other side.

When doing his craft homework, my younger brother didn't have a ruler, so he borrowed mine to draw straight lines.

The carpenter took a long ruler out of the toolbox and carefully measured the length of the wooden board.