57=a^4 convert this into logarithmic form

I think it’s logA(57)=4

Log 57 = log(a)^4 By the law of logs, bring the power down to be multiplied by th log of a.

4 * log(a) = log (57) 
log (a) = log (57) / 4 Answer

I can't think of a way to make this any more detailed.

If you are interested in the value of a it can be found this way.
log (a) = log(57)/4
log (a) = 1.5779 / 4
log (a) = 0.43897
a = 10^0.43897
a = 2.7477

Cd is the perpendicular bisector of both xy and st, and cy=20.find xy