Envision Math 2.0: Grade 8, Volume 2
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Envision Math 2.0: Grade 8, Volume 2 View details
1. Analyze Translations
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Exercise 13 Page 302

Practice makes perfect

We are given a plot of land shaped like the figure in the following graph.

rectangle whose vertices are the points (20,40), (80,40), (80,100), and (20,100)
We want to draw the image of the plot of land after a translation 120 yards east and 100 yards north. Let's start by labeling all the vertices of the given figure. Since all the vertices lie perfectly on the grid lines, we can easily determine the x-coordinate and the y-coordinate of these points.
rectangle

Translations are done by adding or subtracting values from the x-coordinate if the figure is being moved left or right, and from the y-coordinate if the figure is being moved up or down. We want to draw the image of figure ABCD after a translation 120 yards right and 100 yards up. Therefore, we will add 120 to the x-coordinate and add 100 to the y-coordinate of each vertex.

Vertices of ABCD (x+120,y+100) Vertices of A'B'C'D'
A(20,40) (20 + 120,40 + 100) A'(140,140)
B(20,100) (20 + 120,100 + 100) B'(140,200)
C(80,100) (80 + 120,100 + 100) C'(200,200)
D(80,40) (80 + 120,40 + 100) D'(200,140)
Let's do the translation!
translation
Therefore, the image of figure ABCD after the translation is the figure with vertices A'(140,140), B'(140,200), C'(200,200), and D'(200,140).

We want to find the combined area of the 2 given plots.

rectangle
From Part A we know that one of these figures is a translation of the second figure. Therefore, both figures have the same shape, size, and orientation. This means that they have equal areas. Since both figures are squares, we can use the formula for the area of a square to find their areas.

Area of a Square = a^2 In the formula, a is the side length of a square. We can find the side length of one plot by looking at the graph.

rectangle

Therefore, a= 60. Now we substitute the value of a into the formula and calculate the area of the plot. Area of a Square = 60^2 = 3600 We got that the area of one plot equals 3600 square yards. Since both plots have equal areas, the combined area is equal to 2* 3600 = 7200 square yards.