Question 23002
If the line contains the origin, that means that in the equation of a line 
y=mx+b


the value of b = 0.  All you need is the slope, which is rise over run, up 1 and over 2 to get from (0,0) to (2,1).  The slope m is rise over run = 1/2, so the equation is 

{{{y=(1/2)x+ 0}}} or {{{y=(1/2)x}}}


R^2 at SCC