Today in 'Ask the Editor'
Q. I am writing material that requires Imperial dimensions with parenthetical metric dimensions. Would I write "the 60-foot-tall (20-meter) tree" or "the 60-foot (20-meter) tall tree"? – from Charlotte, N.C. on Sun, Feb 23, 2014
A. The 60-foot-tall (20-meter) tree ...
Dear Charlotte: Neither of the above. A 60-foot tree is about 18.3 meters (18 if you use the feet-to-meters conversion on page 170 of your AP Stylebook, which is a little less accurate than its meters-to-feet counterpart).
Practically, your audience is likely to default to height if that's the only number you mention, so "the 60-foot (18.3-meter) tree" would be fine. But if your style is picky enough to demand both measurements, it's picky enough to tolerate a little arithmetic and a decimal point.