# Aim: What Happens When We Enlarge Or Decrease The Size Of An Object?

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Aim: What Happens When We Enlarge Or Decrease The Size Of An Object?

Do Now Does a dilations always involve a change in size? List three examples to support you answers. Aim: What Happens When We Enlarge Or Decrease The Size Of An Object?

Dilations of everyday occurrences You are probably familiar with the word "dilate" as it relates to the eye. The pupil of the eye dilates (gets larger or smaller) depending upon the amount of light striking the eye. Aim: What Happens When We Enlarge Or Decrease The Size Of An Object?

Definition of a dilation http://www.amathsdictionaryforkids.com/ http://intermath.coe.uga.edu/dictnary/homep g.asp Aim: What Happens When We Enlarge Or Decrease The Size Of An Object?

Dilations that occur in transformational geometry The description of a dilation includes the scale factor and the center of the dilation. A dilation of scalar factor k whose center of dilation is the origin may be written: Dk(x,y) = (kx,ky). Aim: What Happens When We Enlarge Or Decrease The Size Of An Object?

Dilations that occur in transformational geometry If the scale factor is greater than 1, the image is an enlargement. If the scale factor is between 0 and 1, the image is a reduction. Aim: What Happens When We Enlarge Or Decrease The Size Of An Object?

Student Activity Exploring dilations Students will complete the handout as they work with interactive website to explore and understand dilations.handout http://www.learnalberta.ca/content/mejhm/ht ml/object_interactives/dilatations/use_it.ht ml?launch=true Aim: What Happens When We Enlarge Or Decrease The Size Of An Object?

Summary Does location matter when a set of points or an object is dilated in plane? Aim: What Happens When We Enlarge Or Decrease The Size Of An Object?

Additional Resources The next lesson will have students modeling dilations using Geometers Sketchpad.Geometers Sketchpad Homework JMAP HANDOUTJMAP HANDOUT

Standards Standard MST3: Mathematics (1997) Performance Indicator MST3.C.OP3.MB.C: Students use transformations on figures and functions in the coordinate plane. Standard MST3: Mathematics (2005) Performance Indicator MST3.IG.GE8.58: Students define, investigate, justify, and apply similarities (dilations and the composition of dilations and isometries).

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