Explanation:
2 points in a coordinate grid establish a right-angled triangle :
the distance between the points is the Hypotenuse, and the x- and y-coordinate differences are the legs.
and so, Pythagoras applies
c² = a² + b²
with c being the Hypotenuse, and a and b are the legs.
distance² = (-2 - 9)² + (6 - -4)² = (-11)² + (10)² = 121 + 100 =
= 221
distance = sqrt(221) = 14.86606875...