1. NO WARM UP!!!

2. Section 1.8 Distance and Midpoint Formulas
Question to be Answered:
How do you find the distance and midpoint between two points?

3. What do you know? Y-Axis X-axis
In coordinate geometry, you describe a point by an ordered pair (x,y), called the coordinates of the point.

4. The Cartesian Plane. 2
Quadrant 1 4 3

5. What do you know?
Plot P(-3,4), Q(0,0), R(2,4) , S(1,-4)

6. Graph the points A(2,2), B(-4,2), and C(2,-3)

7. Where the crow flies

8. Distance Formula To find the distance between two points that are not on a horizontal or vertical line, you can use the distance formula.

9. “They found that eight crocodiles undertook a total of 42 long-distance journeys of more than 10 kilometers [6.2 miles] per day.”

10. (200,148)
(20,18)
Another croc — a 15.8-foot-long male (4.8 meters) — traveled more than 255 miles (411 km) in only 20 days through the Torres Straits, which are notorious for strong water currents [MSNBC].

11. Let's use it to find the distance between (3, -5) and (-1,4)
Plug these values in the distance formula
(x1,y1)
(x2,y2)
means approximately equal to -1 3 4 -5
CAUTION!
found with a calculator
Don't forget the order of operations!
You must do the parenthesis first then powers (square the numbers) and then add together BEFORE you can square root

12. Distance Formula – you try
1.) (2,6), (5,2)
2.) (3, 7), (4, -2)
3.) (-6, 0), (-3, 4)

13. Mid point Formula (x1,y1) Midpoint is (x2, y2) ½ way between!
Average value of x’s and y’s.
(x2, y2) 2 -7 -6 -5 -4 -3 -2 -1 1 5 7 3 4 6 8

14. ( ) Remember, the midpoint formula is .
Finding the Midpoint Between Two Points
Find the midpoint between the points (–2, 3) and (4, 2).
x 1 + x 2 2 ( )
y 1 + y 2 ,
Remember, the midpoint formula is
SOLUTION

15. Find the Midpoint – you try
1.) (2,6), (5,2)
2.) (3, 7), (4, -2)
3.) (-6, 0), (-3, 4)

16. If the midpoint of AB is M(3,4) and endpoint A is (3,-2), find the coordinates of endpoint B.
(3,4)=
3= =

17. 3= =
2*3= *4=
6=3+x2 8=-2+y2
x2=3 y2=10
(3,10)

18. Quiz Wednesday Homework (2 assignments) Angles worksheet
Distance &midpoint practice sheet