Points A and B are at (9 ,3 ) and (7 ,8 ), respectively. Point A is rotated counterclockwise about the origin by pi and dilated about point C by a factor of 3 . If point A is now at point B, what are the coordinates of point C?
1 Answer
Jul 22, 2018
Explanation:
"under a counterclockwise rotation about the origin of "pi
• " a point "(x,y)to(-x,-y)
A(9,3)toA'(-9,-3)" where A' is the image of A"
vec(CB)=color(red)(3)vec(CA')
ulb-ulc=3(ula'-ulc)
ulb-ulc=3ula'-3ulc
2ulc=3ula'-ulb
color(white)(2ulc)=3((-9),(-3))-((7),(8))
color(white)(2ulc)=((-27),(-9))-((7),(8))=((-34),(-17))
ulc=1/2((-34),(-17))=((-17),(-17/2))
rArrC=(-17,-17/2)