8-1.7 Dilations - 8.7 Dilations 8.7 Pg 506 Dilation...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 8.7 Dilations 8.7 Pg 506 Dilation Dilation • Dilation- a transformation where an Dilationobject (preimage) is enlarged or reduced (image). reduced • The image will always be marked The with primes, such as A’. with Reduction If CP=10 Reduction and CP’=5, k=? Scale factor= k 51 CP ' k= = k= 10 2 CP P preimage Reduction: 0<k<1 0<k<1 center Q’ C P’ Image Q R’ R Enlargement Enlargement Scale factor=k k>1 CP ' k= CP P’ If CP=12 and CP’=36, and k=? k=? P Preimage 36 k= =3 12 Image C R Q Q’ R’ Center Stuff to know Stuff • In dilations, the image and preimage In are similar figures. are • So, since Δ PQR~ Δ P’Q’R’, So, P ' Q ' = scale factor scale PQ ** notice, the primes are on top! Ex: Identify the dilation and calculate the scale factor. the P 3 P’ 4 C reduction CP ' 4 = CP 7 Example: Example (a.) Draw a dilation of Δ ABC w/ A(-2,1), B(-6,0), and C(-1,-1). Use the origin as the center and use a scale factor of 3/2. scale (b.) Is this an enlargement or (b.) reduction? (c.) How does the perimeter of the preimage compare to the perimeter of the image? of (a.) To get the image points, multiply each given point by the scale factor. scale Preimage Multiply by 3/2 A(-2,1) A’(-3,3/2) B(-6,0) B’(-9,0) C(-1,-1) C’(-3/2,-3/2) B’ . B A’ A . Image C C’ . 6 4 2 (b.) Is this an (b.) enlargement or reduction? reduction? 5 -5 -2 -4 Enlargement, Enlargement, because the scale factor is > 1. factor -6 (c.) So, how does the perimeter of does the preimage compare to the perimeter of the image? perimeter • Since the ratio of the perimeters is Since the same as the scale factor, the ratio of the perimeters is 3/2. ratio Assignment Assignment ...
View Full Document

This note was uploaded on 02/12/2011 for the course MTG 3212 taught by Professor Jackson during the Spring '11 term at University of Florida.

Ask a homework question - tutors are online