Searching for other information came across this old thread and couldn't resist. Ed, and I'm sure you do remember this,

(any base log would work but I'll just use 10 for this example and ^ for "raise to the power")

log10(X^Y) = Y * log10(X)

So to find the square root of 99,

99 ^ 0.5, now get out the tables or slide rule:

Do the log : log10(99) = 1.996

Multiply for the power : 0.5 * 1.996 = 0.998

Do the antilog to get the result : 10 ^ 0.998 = 9.950

Cube root of 99? 4.626 by same method...