The best way I can explain the elimination method is, it's a method where you either add or subtract equations in order to get rid of a variable.
Yes it is possible to prove this is a parallelogram.
XN = NZ means the diagonal XZ has been bisected
The same goes for diagonal WY (because NY = NW)
Furthermore, we have the pair of vertical angles XNY and ZNW which are congruent
Through SAS, we can say that triangles XNY and ZNW are congruent
Using CPCTC, we can get to the fact that angle NWZ = angle NYX which are alternate interior angles leading to proving that XY || WZ
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If you repeat those steps above, but focus on triangles WNX and YNZ, we can prove that XW || YZ
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After proving that XY || WZ and XW || YZ, this is enough to prove we have a parallelogram as the opposite sides are parallel.
Answer:

Step-by-step explanation:
We are given that
Length of rope=l=160 feet
Radius of quadrant of circle=r=160 feet
We have to find the maximum grazing area of the cow.
We know that
Area of quadrant of circle=
Where 
Using the formula
Area grazed by cow=
Area grazed by cow=
Answer:
this is a function I beleive
hope this helps