Note: The image of G after the dilation must be G'(5,-5) instead of G'(5,5).
Given:
The vertices of a rectangle are E(4,8), F(2,8), G(2,-2) and H(-4,-2).
The rectangle is dilated with the origin as the center of dilation so that G's is located at (5,-5).
To find:
The algebraic representation that represents this dilation.
Solution:
If a figure is dilated by factor k with origin as the center of dilation, then the dilation is defined as:
[tex](x,y)\to (kx,ky)[/tex] ...(i)
Let the given rectangle is dilated by factor k with origin as the center of dilation. Then,
[tex]G(2,-2)\to G'(k(2),k(-2))[/tex]
[tex]G(2,-2)\to G'(2k,-2k)[/tex]
The image of G after dilation is G'(5,-5). So,
[tex](2k,-2k)=(5,-5)[/tex]
On comparing both sides, we get
[tex]2k=5[/tex]
[tex]k=\dfrac{5}{2}[/tex]
So, the scale factor is [tex]k=\dfrac{5}{2}[/tex].
Substituting [tex]k=\dfrac{5}{2}[/tex] in (i), we get
[tex](x,y)\to \left(\dfrac{5}{2}x,\dfrac{5}{2}y\right)[/tex]
Therefore, the required algebraic representation to represents this dilation is [tex](x,y)\to \left(\dfrac{5}{2}x,\dfrac{5}{2}y\right)[/tex].
