it is often used in word problems of finding the distance in a function graph and then finding the coordinates of a point through the distance.

it is known that the coordinates of two points a and b are a(x1,y1) and b(x2,y2) respectively.

the square of the distance ab between two points is

AB²=(x1-x2)²+(y1-y2)²

calculate the square root to get the distance ab.

for example: it is known that the coordinates of two points a and b are a(1,2) and b(4,6) respectively.

AB²=(1-4)²+(2-6)²=25

AB=√25=5

it can also be calculated directly:

AB=√[(1-4)²+(2-6)²]=√25=5