First, evaluate the numerator of the fraction on the right side of the equation:
#0.336 = (1.96 * 4.2)/sqrt(s)#
#0.336 = 8.232/sqrt(s)#
Next, multiply each side of the equation by #color(red)(sqrt(s))# to eliminate the fraction and keeping the equation balanced:
#0.336 xx color(red)(sqrt(s)) = 8.232/sqrt(s) xx color(red)(sqrt(s))#
#0.336sqrt(s) = 8.232/color(red)(cancel(color(black)(sqrt(s)))) xx cancel(color(red)(sqrt(s)))#
#0.336sqrt(s) = 8.232#
Then, divide each side of the equation by #color(red)(0.336)# to isolate the radical while keeping the equation balanced:
#(0.336sqrt(s))/color(red)(0.336) = 8.232/color(red)(0.336)#
#(color(red)(cancel(color(black)(0.336)))sqrt(s))/cancel(color(red)(0.336)) = 24.5#
#sqrt(s) = 24.5#
Now, square both sides of the equation to solve for #s# while keeping the equation balanced:
#(sqrt(s))^2 = 24.5^2#
#s = 600.25#