Lets say w is the width of the flower bed. We can make an equation to find the area.
The length of the of the flower bed is (w+5) and the width is w.
To find the area we need to multiply the length(w+5) by the width(w) and set it equal to 84,
(w+5)(w)=84
w^2 +5w=84
Using the quadratic equation you get the solutions of 7 and -12. Since 7 is positive it is our width. Our length is 7+5 or 12.
Answer:
Here are the answer to your question
1. Rhombus
2. Diagonals are congruent
Here is the answer for the rest of the quick check if anyone needs them
3. Diagonals are perpendicular and diagonals are congruent
4. 4