Draw an iceberg and see what part of it appears above the water's surface on Joshua Tauberer's fun interactive web page.
Icebergs are less dense than water, so they always float with about 10% of their mass above the water. But which way up? An iceberg wouldn't float exactly like on this page in reality. Its three-dimensional distribution of mass and its relative density compared to the water are both significant factors that are only approximated here.