Answer:
The length is 9.
The width is 7.
Step-by-step explanation:
A rectangle has two dimensions.
The width, which is the distance between the points who have the same value of y.
The length, which is the distance between the points who have the same value of x.
Distance between 2 points:
Points (a,b) and (c,d).
Same value of x:
(-1,1), (-1-8) or (6,1), (6,-8)
The distance for both of them is the same, can calculate for only one.
The length is 9.
Same value of y:
(-1,1), (6,1) or (6,-8), (-1,-8)
The width is 7.