About 7.9 in
Work Step by Step
apothem=.5s$\sqrt 3$ a=.5(6$\sqrt 3$)($\sqrt 3$) a=9 h$^2$=l$^2$-a$^2$ h$^2$=144-81 h$^2$=63 h=$\sqrt 63$ h$\approx$7.9
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