TODAY IN GEOMETRY…

STATs for Ch.8 Test

Learning Target : 9.1 Given a pre-image, create an image by transformation by translation/slide or reflection

Independent Practice

Ch.8 Retakes

HOW DID YOU “SHAPE” UP??Results for ALL of my Geometry classes:

GRADE NUMBER OF STUDENTS WHO TOOK THE CH.8 TEST (35 pts)

3RD PERIOD 4TH PERIOD 5TH PERIOD TOTAL

A/A- 10 9 11 30B+/B/B- 4 9 9 22C+/C/C- 3 2 4 9

D+/D 5 3 1 9F 5 6 2 13

Average 26.33 26.80 29.15

PRE-IMAGE: Starting figure of a transformation labeled as

IMAGE: Ending figure of a transformation labeled as

TRANSLATION/SLIDE: Moves every point of a figure the same distance in the same direction

𝐴𝐵

𝐶𝐷

𝐴 ′𝐵 ′

𝐶 ′𝐷 ′

𝐴 ′ ′𝐵 ′ ′

𝐶 ′ ′𝐷 ′ ′

Translated/slide 7 units right

Translated/slide 8 units down

x-coordinates change by adding 7

y-coordinates change by subtracting 8

TRANSLATION/SLIDE:

(−5 ,5)→(2 ,5)

PRACTICE: Graph . Translate the Pre-Image and record the image points.

𝐴𝐵

𝐶

𝐴 ′𝐵 ′

𝐶 ′

PRACTICE: Write a rule for the translation of the quadrilateral to quadrilateral .

How did the quadrilateral move?To the right 6 Down 6

Right/Up = ADDLeft/Down = SUBTRACT

Rule:

𝐴𝐵

𝐶 𝐷𝐴 ′𝐵 ′

𝐶 ′ 𝐷 ′

In Class Work #1:

Pg. 576: 3-14, 31

20 minutes then you will turn it in then we are moving on to

reflection.

REFLECTION across the x-axis:

𝐴𝐵

𝐶𝐷

Reflection across the x-axis so the x-axis is the mirror

5

5

𝐴 ′

𝐷′

𝐵′

𝐶 ′

Notice that all x-coordinates of the pre-image and image DOESN’T change but the y-coordinates change signs!RULE:

The distances from the mirror to each point is equal!

REFLECTION across the y-axis:

𝐴𝐵

𝐶𝐷

Reflection across the y-axis so the y-axis is the mirror

33𝐵′

𝐶 ′𝐷′

𝐴′

Notice that all y-coordinates of the pre-image and image DOESN’T change but the x-coordinates change signs!RULE:

The distances from the mirror to each point is equal!

REFLECTION across line :

𝐴𝐵

𝐶𝐷

Reflection across the line

𝐵′𝐶 ′

𝐷′

𝐴′

Notice that the x and y coordinates switch values from pre-image to image.RULE:

REFLECTION across line :

𝐴𝐵

𝐶𝐷

Reflection across the line

𝐷′𝐴 ′

𝐵′

𝐶 ′

Notice that the x and y coordinates switch values from pre-image to image.RULE:

REFLECTION:

(−5 ,5)→(2 ,5)𝑥− 𝑦 (−5 ,5)→(−5 ,−5)−𝑥 𝑦 (−5 ,5)→(5 ,5)

(𝑥 , 𝑦 )→(𝑦 , 𝑥) (−5 ,5)→(5 ,−5)(𝑥 , 𝑦 )→(− 𝑦 ,− 𝑥) (−5 ,5)→(−5 ,5)

PRACTICE: Graph . Reflect the pre-image across the y-axis.

RULE FOR RELECTION ACROSS Y-AXIS:

𝐴𝐵

𝐶

𝐴 ′ 𝐵 ′

𝐶 ′

PRACTICE: Graph . Reflect the pre-image across the line .EACH POINT IN A REFLECTION IS EQUAL DISTANT FROM THE LINE OF REFLECTION

𝐴𝐵

𝐶

𝐴 ′ 𝐵 ′

𝐶 ′

𝑥=1

HOMEWORK #1:

Pg.576: 3-14, 31