http://www.ck12.org Chapter 3. Parallel and Perpendicular Lines
d=√
( 3 − 1 )^2 +(− 1 − 5 )^2
=
√
( 2 )^2 +(− 6 )^2
=
√
2 + 36
=
√
38 ≈ 6. 16 unitsWatch this video for help with the Examples above.
MEDIA
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URL: http://www.ck12.org/flx/render/embeddedobject/52450CK-12 Foundation: Chapter3DistanceFormulaintheCoordinatePlaneB
Vocabulary
The√ distance formulatells us that the distance between two points(x 1 ,y 1 )and(x 2 ,y 2 )can be defined asd=
(x 2 −x 1 )^2 +(y 2 −y 1 )^2.Guided Practice
- Find the distance between (-2, -3) and (3, 9).
- Find the distance between (12, 26) and (8, 7).
- Find the shortest distance between (2, -5) andy=−^12 x+ 1
Answers:
- Use the distance formula, plug in the points, and simplify.
d=√
( 3 −(− 2 ))^2 +( 9 −(− 3 ))^2
=
√
( 5 )^2 +( 12 )^2
=
√
25 + 144
=
√
169 = 13 units- Use the distance formula, plug in the points, and simplify.
d=√
( 8 − 12 )^2 +( 7 − 26 )^2
=
√
(− 4 )^2 +(− 19 )^2
=
√
16 + 361
=
√
377 ≈ 19. 42 units