A, C and D because the angles are named in order. Q=T R=U and so on
Answer: 82 sq. units .
Step-by-step explanation:
Let A (9, −1), B (−1, 7), C(−5, 2), D(5, −6) are the vertices of rectangle.
Then we plot them on graph ( as provided in attachment)
Length = AB
units [By distance formula :
]
units
Width = BC =
units

Area = length x width
= 
Hence, the area of the rectangle is 82 sq. units .
Answer: The ice sheet's thickness decrease every 6 weeks= 1.5 meters
Step-by-step explanation:
GIven: At the beginning of spring, the ice starts to melt. The variable sss models the ice sheet's thickness (in meters) t weeks after the beginning of spring. 
At t=0, 
So, Thickness of ice sheet at the beginning = 4 meters
Now at t= 6, we get

Thickness of ice sheet after 6 weeks = 2.5 meters
Decrease in thickness = 4 meters - 2.5 meters = 1.5 meters
Hence, the ice sheet's thickness decrease every 6 weeks= 1.5 meters
Step-by-step explanation:
it's explained in the solution