1. Distance between 2 points Mid-point of 2 points
COORDINATE GEOMETRY
Distance between 2 points
Mid-point of 2 points

2. Distance between two points.y
Using Pythagoras’ Theorem,
B(18,17)
AB2 = (18 - 5)2 + (17 - 3)2 17
AB2 =
17 – 3 = 14 units 3
A(5,3)
18 – 5 = 13 units x 5 18

3. Distance between two points. In general,y
B(x2,y2)
AB2 = (y2-y1)2 + (x2-x1)2 y2
Hence, the formula for Length of AB or Distance between A and B is
Length = y2 – y1 y1
A(x1,y1)
Length = x2 – x1 x x1 x2

4. Find the distance between the points (-1,3) and (2,-6)
Simply by using the formula:
(-1,3) and (2,-6)
(x1,y1) and (x2,y2)
Since
= 9.49 units (3 sig. fig)

5. The mid-point of two points.
Look at it’s horizontal length y
Mid-point of AB
B(18,17) 17
= 11.5
(11.5,
10)
Look at it’s vertical length 10 3
A(5,3)
11.5
= 10 x 5 18

6. The mid-point of two points.
Look at it’s horizontal length y
B(18,17)
Mid-point of AB y2
Look at it’s vertical length
Formula for mid-point is y1
A(5,3) x x1 x2