Points A and B are at (2 ,9 )(2,9) 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 4 4. If point A is now at point B, what are the coordinates of point C?
1 Answer
Feb 5, 2018
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)
rArrA(2,9)toA'(-2,-9)" 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)(rArr3ulc)=4((-2),(-9))-((8),(6))
color(white)(rArr3ulc)=((-8),(-36))-((8),(6))=((-16),(-42))
rArrulc=1/3((-16),(-42))=((-16/3),(-14))
rArrC=(-16/3,-14)