Find the distance using the distance formula, A (0, 9) and B (4, 1).?

d² = 4² + (-8)²
d² = 16 + 64
d² = 80
d = 4 √5

The distance formula is derived from the Pythagorean theorem. To find the distance between two points (x1,y1) and (x2,y2), all that you need to do is use the coordinates of these ordered pairs and apply the formula.

√(x2 - x1)² + (y2 - y1)²

Application:
Your co-ordinates are: (0, 9) and (4, 1)
x1 = 0
x2 = 4
y1 = 9
y2 = 1

1.√(1-9)² + (4-0)²

2.√(-8)² + (4)²

3.√64 + 16 Note: (-8 x -8 = +64)

4.√80

5.√16 x √5 (break the value down)

6. 4√5 is your answer

4 square root 5 because...
9-1=8
8 squared= 64
0-4=-4
-4 squared=16
64+16=80
square root 80= 4 square root 5

just remember this formula: