When a rectangle is dilated, how do the perimeter and area of the rectangle change?
1 answer:
A transformation of a figure in which all of the dimensions of the figure are multiplied by the same scale factor is called a dilation.
Effect of Dilation on Perimeter
Whenever a figure is dilated by a scale factor, the perimeter of the figure changes according to the same scale factor.
Effect of Dilation on Area
When a figure is dilated by a scale factor of , the area of the figure is dilated by a scale factor of
Example-
Lets imagine a rectangle with length 10 cm and width 8 cm
So area becomes = 10*8 = 80 square cm
Lets suppose the rectangle is reduced by a scale factor of to produce a new rectangle.
So we will find the square of scale factor =
Now to find the area of the new rectangle(dilated one) we will multiply the area of the original rectangle by 1/4
=
Hence, area becomes 20 square cm.
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All the points that are 6 units from (-1, 1) are those on the circle
(x+1)^2 +(y-1)^2 = 36
For y=0, the two points of interest satisfy
(x+1)^2 +1 = 36
(x+1)^2 = 35 . . . . . . subtract 1
x+1 = ±√35
x = -1±√35
The points you seek are (-1-√35, 0) and (-1+√35, 0), about (-6.916, 0) and (4.916, 0).
(x+1)^2 +(y-1)^2 = 36
For y=0, the two points of interest satisfy
(x+1)^2 +1 = 36
(x+1)^2 = 35 . . . . . . subtract 1
x+1 = ±√35
x = -1±√35
The points you seek are (-1-√35, 0) and (-1+√35, 0), about (-6.916, 0) and (4.916, 0).