Step-by-step explanation:
the distance formula
d = sqrt((x2 - x1)² + (y2 - y1)²)
is simply based on the Pythagoras formula
c² = a² + b²
or
c = sqrt(a² + b²)
because the distance between 2 points is the Hypotenuse of a right-angled triangle with the legs being the x coordinate difference and the y coordinate difference of the 2 points.
so, in our case here
d = sqrt((10 - -1)² + (5 - 2)²) = sqrt(11² + 3²) = sqrt(121 + 9) =
= sqrt(130) = 11.40175425... ≈ 11.4
