A line segment goes from (3 ,1 )(3,1) to (2 ,4 )(2,4). The line segment is dilated about (2 ,2 )(2,2) by a factor of 33. Then the line segment is reflected across the lines x = 4x=4 and y=-1y=1, in that order. How far are the new endpoints form the origin?

1 Answer
Apr 12, 2018

color(indigo)("Distances of A and B from origin after dilation and reflection "Distances of A and B from origin after dilation and reflection

color(indigo)(3.16, 12.65 " respectively"3.16,12.65 respectively

Explanation:

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

A' (x,y) =3 * A(x,y) - C (x,y) =(( 9 ,3) - (2,2)) = (7,1)

B'(x,y) = 3 ^ B (x,y) - C(x,y) = ((6,12) - (2,2)) = (4,10)

color(brown)("reflect thru " x = 4, y = -1, h=4, k= -1. (2h-x, 2k-y)"

A''(x,y) = (2h-x, 2k-y) = ((8 - 7), (-2-1)) = (1,-3)

"similarly " B''(x,y) = ((8-4),(-2-10)) = (4, -12)

bar(A''O) = sqrt(1^2 + 3^2) = sqrt 10 = 3.16

bar(B''O) = sqrt(4^2 + 12^2) = sqrt 160 = 12.65