Answer: This is a 1 by 5 rectangle
perimeter = 12 units
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Work Shown:
Label the vertices A,B,C,D
A = (1, 4)
B = (1, 5)
C = (6, 5)
D = (6, 4)
The x coordinates of points A and B are the same (x = 1). The difference in y values of these points is 5-4 = 1 unit. This is the height of the rectangle. In other words, it's the length of segment AB.
Points B and C have the same y coordinate (y = 5). The difference in x value is 6-1 = 5 which is the horizontal length of the rectangle. This is the length of segment BC.
In short, this is a 1 by 5 rectangle. It's one unit tall and five units across.
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Perimeter = 2*(length+width)
Perimeter = 2*(5+1)
Perimeter = 2*6
Perimeter = 12 units
Or you can add up the four sides (1,5,1 and 5) to get the same result.