$ perl marpa-scannerless-calculator.pl --stdin
W=1; ( ( 0.3802 + ( 13.4739 * ( ( W / 0.9 )^(1/2) ) ) ) + ( 4.6272 * ( W / 0.9 ) ) )
^Z
result = 19.7242709884476
value of "W" = "1"

##</code><code>##

$ perl -E " $W=1; say ( ( 0.3802 + ( 13.4739 * sqrt( ( $W / 0.9 ) ) ) ) + ( 4.6272 * ( $W / 0.9 ) ) ); "
19.7242709884476