A line segment goes from (2 ,3 )(2,3) to (4 ,1 )(4,1). The line segment is dilated about (1 ,1 )(1,1) by a factor of 22. Then the line segment is reflected across the lines x=2x=2 and y=-1y=1, in that order. How far are the new endpoints from the origin?

1 Answer
Apr 12, 2018

"Distance of the two points from origin after dilation and reflection "Distance of the two points from origin after dilation and reflection
color(blue)( 3.16, 4.24)3.16,4.24

Explanation:

A (2,3), B (4,1) " dilated about " C (1,1) " by a factor of 2"A(2,3),B(4,1) dilated about C(1,1) by a factor of 2

A'(x,) = 2 * A(x,y) - C(x,y) =( (4,6) - (1,1)) = (3,5)

B'(x,) = 2 * B(x,y) - C(x,y) =( (8,2) - (1,1)) = (7,1)

color(crimson)("reflect thru across " x=2, y = -1, h=2 k= -1. (2h-x, 2k-y)"

A''(x,y) = (2*2 - 3), (2*-1 - 5) = (1,-3)

B''(x,y) = (2 * 2 - 7), (2*-1 - 1) = (-3, -3)

A''O = sqrt(1^2 + 3^3) = 3.16

B''O = sqrt(3^2 + 3^2) = 4.24