Finding the distance between two points is simply a matter of plugging the points' coordinates into a formula and the distance comes out the other end. The formula is: SQR((X1-X2)SQ + (Y1-Y2)SQ) where SQR means square root, and SQ means squared. The number after the x or y signifies which point the coordinate belongs to. 1 for the first point, 2 for the second point. Let's put this into action:

Point A - (1,1) Point B - (4,5)

SQR((1-4)SQ + (1-5)SQ)

SQR((-3)SQ + (-4)SQ)

SQR(9 + 16)

SQR(25)

5

The distance between points A and B is 5.

This formula can also be used to find the lengths of line segments. Just use the two endpoints as the points in the formula, and off you go!

Practice time!

Use this graph for numbers 1 - 5.

Find the distance between the two listed points -

1) B and E

2) C and D

3) B and D

4) C and A

5) B and A

Use this graph for numbers 6 - 8.

6) Find the perimeter of triangle ABC

7) Find the area of triangle ABC

8) Find the slope of AB