Points A and B are at (5 ,8 ) and (8 ,1 ), respectively. Point A is rotated counterclockwise about the origin by pi and dilated about point C by a factor of 4 . If point A is now at point B, what are the coordinates of point C?

1 Answer
Jan 14, 2018

C=(-40/3,-7)

Explanation:

"under a counterclockwise rotation about the origin of "pi

• " a point "(x,y)to(-x-y)

rArrA(5,8)toA'(-8,-5)" where A' is the image of A"

rArrvec(CB)=color(red)(4)vec(CA')

rArrulb-ulc=4(ula'-ulc)

rArrulb-ulc=4ula'-4ulc

rArr3ulc=4ula'-ulb

color(white)(rArrul3c)=4((-8),(-5))-((8),(1))

color(white)(rArrul3c)=((-32),(-20))-((8),(1))=((-40),(-21))

rArrulc=1/3((-40),(-21))=((-40/3),(-7))

rArrC=(-40/3,-7)