Points A and B are at (3 ,7 ) and (6 ,1 ), respectively. Point A is rotated counterclockwise about the origin by pi/2 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
Jun 5, 2018
Explanation:
"under a counterclockwise rotation about the origin of "pi/2
• " a point "(x,y)to(-y,x)
A(3,7)toA'(-7,3)" where A' is the image of A"
vec(CB)=color(red)(4)vec(CA')
ulb-ulc=4(ula'-ulc)
ulb-ulc=4ula'-4ulc
3ulc=4ula'-ulb
color(white)(3ulc)=4((-7),(3))-((6),(1))
color(white)(3ulc)=((-28),(12))-((6),(1))=((-34),(11))
ulc=1/3((-34),(11))=((-34/3),(11/3))
rArrC=(-34/3,11/3)