Points A and B are at (6 ,5 )(6,5) and (7 ,8 )(7,8), respectively. Point A is rotated counterclockwise about the origin by pi/2 π2 and dilated about point C by a factor of 2 2. If point A is now at point B, what are the coordinates of point C?

1 Answer
Mar 21, 2018

C=(-17,4)C=(17,4)

Explanation:

"under a counterclockwise rotation about the origin of "pi/2under a counterclockwise rotation about the origin of π2

• " a point "(x,y)to(-y,x) a point (x,y)(y,x)

rArrA(6,5)toA'(-5,6)" where A' is the image of A"

rArrvec(CB)=color(red)(2)vec(CA')

rArrulb-ulc=2(ula'-ulc)

rArrulb-ulc=2ula'-2ulc

rArrulc=2ula'-ulb

color(white)(rArrulc)=2((-5),(6))-((7),(8))

color(white)(rArrulc)=((-10),(12))-((7),(8))=((-17),(4))

rArrC=(-17,4)