Question

A rectangle has vertices 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' is located at (5, -5). Which algebraic representation represents this dilation?

Answer 1

Answer:

The dilation on any point of the rectangle is $P'(x,y) = \frac{5}{2}\cdot P(x,y)$.

Step-by-step explanation:

From Linear Algebra, we define the dilation of a point by means of the following definition:

$G'(x,y) = O(x,y) +k\cdot [G(x,y)-O(x,y)]$ (1)

Where:

$G(x,y)$ - Coordinates of the point G, dimensionless.

$O(x,y)$ - Center of dilation, dimensionless.

$k$ - Scale factor, dimensionless.

$G'(x,y)$ - Coordinates of the point G', dimensionless.

If we know that $O(x,y) = (0,0)$, $G(x,y) =(2,-2)$ and $G'(x,y) =(5,-5)$, then scale factor is:

$(5,-5) = (0,0) +k\cdot [(2,-2)-(0,0)]$

$(5,-5) = (2\cdot k, -2\cdot k)$

$k = \frac{5}{2}$

The dilation on any point of the rectangle is:

$P'(x,y) = (0,0) + \frac{5}{2}\cdot [P(x,y)-(0,0)]$

$P'(x,y) = \frac{5}{2}\cdot P(x,y)$ (2)

The dilation on any point of the rectangle is $P'(x,y) = \frac{5}{2}\cdot P(x,y)$.