Question 20912
FORMULA FOR DISTANCE BETWEEN 2 POINTS (X1,Y1) AND (X2,Y2)
= [(X2-X1)^2+(Y2-Y1)^2]^0.5...HENCE 
DISTANCE BETWEEN (1,1) AND (2,3)=[(2-1)^2+(3-1)^2]^0.5=(1^2+2^2)^0.5=(5)^0.5=SQUARE ROOT OF 5