Question 168447
when they say y varies directly that just means {{{y=x^2}}} now the trick is getting the numbers,  so right now if we make {{{x=0.1}}} then {{{y=0.01}}}, this is not what we want, now to make 0.01 into 0.4 you multiply by 40, and do the same to the equation, so now {{{y=40x^2}}}, and if you plug 0.1 in you get {{{y=40*0.1*0.1=0.4}}}