Calculate the distance between the points (Point Difference Calculator)  

Apply Formula and substitute the values:
√(x2x1)^{2} + (y2y1)^{2}
= √(2 (1))^{2} + (21)^{2}
=√(2+1)^{2}+(1)^{2}
=√(1)^{2}+(1)^{2}
=√1+1
=√2