lesson 9-6 pages 466-470 the distance and midpoint formulas lesson check 9-5
TRANSCRIPT
Lesson 9-6 Pages 466-470
The Distance and Midpoint Formulas
Lesson Check 9-5
What you will learn!1. How to use the Distance
Formula to determine lengths on a coordinate plane.
2. Use the Midpoint Formula to find the midpoint of a line segment on the coordinate plane.
Distance FormulaDistance FormulaMidpointMidpointMidpoint FormulaMidpoint Formula
What you really need to know!
On a coordinate plane, the distance between two points with coordinates (x1 , y1) and (x2 , y2) is given by:
212
212 )()( yyxxd
What you really need to know!
The midpoint of a line segment whose endpoints are (x1 , y1) and (x2 , y2) is given by:
2
)(,
2
)( 2121 yyxx
Example 1:
Find the distance between M(8 , 4) and N(-6 , -2). Round to the nearest tenth, if necessary.
212
212 )()( yyxxd
22 )42()86( d
22 )42()86( d22 )6()14( d
36196d
232d
232d
11727915.2315462d
15.2d
Example 2:
Find the perimeter of ∆XYZ to the nearest tenth.
Side XY: X(-5 , 1), Y(-2 , 4)
212
212 )()( yyxxd
22 )14()52( d22 )3()3( d
18d
Side XZ: X(-5 , 1), Z(-3 , -3)
212
212 )()( yyxxd
22 )13()53( d22 )4()2( d
20d
Side YZ: Y(-2 , 4), Z(-3 , -3)
212
212 )()( yyxxd
22 )43()23( d22 )7()1( d
50d
502018 P
53984315.7858444P
15.8P
Example 3:
Find the coordinates of the midpoint of RS.
2
)( 21 xx
2
)( 21 yy
2
)( 21 xx
2
)( 21 yy
2
)82( 2
)6( 3
2
)24( 2
)6( 3)3,3(
Page 468
Guided Practice
#’s 4-8
Pages 466-468 with someone at home and
study examples!
Read:
Homework: Pages 469-470
#’s 10-30 even
#’s 33-48
Practice Quiz 2 #’s 1-5Lesson Check 9-6
Page
746
Lesson 9-6
Lesson Check 9-6