Points A and B are at (9 ,7 )(9,7) and (8 ,6 )(8,6), respectively. Point A is rotated counterclockwise about the origin by pi π 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
Jun 22, 2018

C=(-26,-20)C=(26,20)

Explanation:

"under a counterclockwise rotation about the origin of "piunder a counterclockwise rotation about the origin of π

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

A(9,7)toA'(-9,-7)" where A' is the image of A"

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

ulb-ulc=2(ula'-ulc)

ulb-ulc=2ula'-2ulc

ulc=2ula'-ulb

color(white)(ulc)=2((-9),(-7))-((8),(6))

color(white)(ulc)=((-18),(-14))-((8),(6))=((-26),(-20))

rArrC=(-26,-20)