help me to understand how to determine the volume in a partial graduated cylinder etc., 45 &40
The liquid level rises to a scale value that equals the volume in milliliters (usually). You will have to use the scale to interpolate between printed numbers.
This picture may help:
http://www.google.com/imgres?q=graduated+cylinder&um=1&hl=en&client=firefox-a&sa=N&rls=org.mozilla:en-US:official&biw=1207&bih=654&tbm=isch&tbnid=0DRBMuTOcecFLM:&imgrefurl=http://jchemed.chem.wisc.edu/JCESoft/Programs/CPL/Sample/modules/gradcyl/grad100mL.htm&docid=_oBhuX2MEgvxvM&w=320&h=240&ei=WmFOTprkL6jkiAKK6-mUAQ&zoom=1&iact=hc&vpx=452&vpy=222&dur=10889&hovh=192&hovw=256&tx=140&ty=120&page=1&tbnh=113&tbnw=151&start=0&ndsp=22&ved=1t:429,r:2,s:0