Distance Formula

Mrs. King

Geometry

Unit 12, Day 8

Getting Started…

Kayleigh walks to a friend’s house by traveling 5 blocks west and then 12 blocks north. She returns home later by cutting diagonally through her neighbors’ yards. What distance did she travel on her voyage home?

Kayleigh’s Journey…222 cba 222 125 c214425 c

2169 c2169 c

c135

1213

Distance on the coordinate plane The distance between two points and

on the coordinate plane (graph) can be found using the formula:

221

221 yyxxd

11, yx 22 , yx

http://www.bsin.k12.nm.us/schools/BHS/math/joinmath/geometry/GEO1_3.pps#257,4,Slide 4

Find the distance between (-3, 2) and (4, 1)

x1 = -3, x2 = 4, y1 = 2 , y2 = 1

( 3 4)2 (2 1)2d =

( 7)2 (1)2 49 1d =

50 or 5 2 or 7.07d =

2 22 1 2 1( ) ( )x x y y

Example:

http://teachers.henrico.k12.va.us/math/igo/01Fundamentals/1-3Formulas/LECTURE1-3.ppt#259,3,The Distance Formula

Homework

Work Packet: Distance Formula