Points A and B are at (2 ,7 )(2,7) and (4 ,6 )(4,6), respectively. Point A is rotated counterclockwise about the origin by pi π and dilated about point C by a factor of 3 3. If point A is now at point B, what are the coordinates of point C?
1 Answer
Mar 21, 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(2,7)toA'(-2,-7)" where A' is the image of A"
rArrvec(CB)=color(red)(3)vec(CA')
rArrulb-ulc=3(ula'-ulc)
rArrulb-ulc=3ula'-3ulc
rArr2ulc=3ula'-ulb
color(white)(rArr2ulc)=3((-2),(-7))-((4),(6))
color(white)(rArr2ulc)=((-6),(-21))-((4),(6))=((-10),(-27))
rArrulc=1/2((-10),(-27))=((-5),(-27/2))
rArrC=(-5,-27/2)