Assertion: piano's key | /r/CapableOf | average 13.7 mm
Facets:
Source sentences:
text: Modern piano keyboards ordinarily have an octave span of 164–165 mm (6.5–6.5 in); resulting in the width of black keys averaging 13.7 mm (0.54 in) and white keys about 23.5 mm (0.93 in) wide at the base, disregarding space between keys.
text: Modern piano keyboards tend to have an octave span of 161 to 167mm; resulting in the width of black keys averaging 13.7 mm and white keys about 23.5 mm wide.