Algebra 1 Common Core Student Edition, Grade 8-9

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Review

Use W ith Lesson 1 -9

ing in the

Co o r d i n a t e Pl an e

@1 Common Core State Standards

Prepares fo r A-CED.A.2 ... graph equations on

coordinate axes w ith labels and scales.

T w o n u m b e r lin e s t h a t in t e r s e c t a t r i g h t a n g le s f o r m a coordinate plane. The

horizontal axis is the x-axis and the vertical axis is the y-axis. The axes intersect at

the origin and divide the coordinate plane into four sections called quadrants.

An ordered pair of numbers names the location of a point in the plane. These

num bers are the coordinates of the point. Point B h a s c o o rd in a te s ( - 3 , 4 ).

The first coordinate

is the x-coordinate. (-3 ,4 )

The second coordinate

is the y-coordinate.

T o r e a c h t h e p o i n t (x , y ) , y o u u s e th e x - c o o r d in a t e t o t e l l h o w f a r t o m o v e r i g h t

( p o s it iv e ) o r le f t ( n e g a t iv e ) f r o m th e o r ig in. Y o u t h e n u s e th e y - c o o r d in a t e t o t e l l h o w

f a r t o m o v e u p ( p o s it iv e ) o r d o w n ( n e g a t iv e ).

Activity

Play against a partner using two number cubes and a coordinate grid. One cube

represents positive numbers and the other cube represents negative numbers.

• D u r in g e a c h t u r n , a p la y e r r o lls b o t h c u b e s a n d a d d s th e n u m b e r s t o f i n d a n
  x - c o o r d in a t e. B o t h c u b e s a re r o lle d a s e c o n d t im e , a n d th e n u m b e r s a re a d d e d t o
  f i n d th e y - c o o r d in a t e. T h e p la y e r g r a p h s th e r e s u lt in g o r d e r e d p a i r o n th e g r id.


• The tw o players take turns, w ith each player using a different color to graph
  p o in ts. I f a n o r d e r e d p a i r h a s a lr e a d y b e e n g r a p h e d , th e p la y e r d o e s n o t g r a p h a
  point, and the turn is over.


• P la y e n d s a fte r e a c h p la y e r h a s c o m p le t e d 10 tu r n s. T h e p la y e r w i t h t h e m o s t
  p o in t s g r a p h e d i n a q u a d r a n t s c o re s 1 f o r Q u a d r a n t I, 2 f o r Q u a d r a n t I I , a n d so o n.
  Points graphed on either axis do not count. If both players graph an equal num ber
  of points in a quadrant, both players score 0 f o r t h a t q u a d r a n t.

Ex e r c i se s

Describe a pair of number cube rolls that would result in a point plotted at the given

location.

y~axi s

(--3, 4)

Qtad ra i t^1 Qijad ra nt^1

* 0

;r-a <is

Qu ad ran 1 1II Qu ad ran t lv

__ 1

1. (-3 ,4 ) 2. (4, - 3 ) 3. i n Q u a d r a n t I I I 4. the o rig in

60 Ch ap t er 1 Review