Question 983524


First, &nbsp;compute the vector &nbsp;<B>EF</B>&nbsp; (with the start-point &nbsp;<B>E</B>&nbsp; and the end-point &nbsp;<B>F</B>) &nbsp;in the coordinate form


&nbsp;<B>EF</B> = (1 - (-8), 1 - 1) = (9, 0).


In other words, &nbsp;x-component &nbsp;dx = 1 - (-8) = 9 &nbsp;and &nbsp;y-component &nbsp;dy = 1 - 1 = 0.


Now, &nbsp;the length of the vector &nbsp;<B>EF</B>&nbsp; is 


{{{sqrt(dx^2 + dy^2)}}} = {{{sqrt(9^2 + 0^2)}}} = {{{sqrt(81)}}} = 9.