Answer: (a) 36.07km, (b) 253.2°
(c) 19.18km
Step-by-step explanation:
Answer:
Rhombus
Step-by-step explanation:
The given points are A(−5, 6), B(−1, 8), C(3, 6), D(−1, 4).
We use the distance formula to find the length of AB.



The length of AD is



The length of BC is:



The length of CD is



Since all sides are congruent the quadrilateral could be a rhombus or a square.
Slope of AB
Slope of BC 
Since the slopes of the adjacent sides are not negative reciprocals of each other, the quadrilateral cannot be a square. It is a rhombus
So you need to do substitution. First solve the easier equation for 1 variable.
x+y=-1 now subtract x to get y=-x-1. Then plug this into the top equation to get 2x+7(-x-1)=2. Next distribute to get 2x+-7x-7=2. Now combine like terms to get -5x=9 so x=-5/9. Now you have to plug this back into the original equation to get y. 2(-5/9)+7y=2, so -10/9 +7y=2. No move terms around to get 7y=28/9 then divide by 7 to get y= 4/9