The definition is pretty simple:

So, we only have to sum the expressions:

6/10, 9/15,12/20,15/25
Those are all equal to 3/5.
Hope this helps and hope you have a great day
<h2>
Explanation:</h2>
In every rectangle, the two diagonals have the same length. If a quadrilateral's diagonals have the same length, that doesn't mean it has to be a rectangle, but if a parallelogram's diagonals have the same length, then it's definitely a rectangle.
So first of all, let's prove this is a parallelogram. The basic definition of a parallelogram is that it is a quadrilateral where both pairs of opposite sides are parallel.
So let's name the vertices as:

First pair of opposite sides:
<u>Slope:</u>

Second pair of opposite sides:
<u>Slope:</u>

So in fact this is a parallelogram. The other thing we need to prove is that the diagonals measure the same. Using distance formula:

So the diagonals measure the same, therefore this is a rectangle.
180-2(55)-x=0
180-110-x=0
70-x=0
-x=-70
x=70°
Area of square
= 7x7
=49
Area of triangle
=0.5x 7x12
=42
Total area of figure
=49+42
=91
Hence, answer is D