the extendedDataTable component comes with an attribute width, which you can specify with number of pixels or a percentage value. But the attribute height does not allow you to enter a percentage value.
Is it possible to make the table have a dynamic height or dynamic number of rows shown?
you could check for some possible workarounds (there were some issues in jira with community comments) but it's not available in 3.3 out of the box. But 4.x table already supports it.