Area of the big triangle (shaded area and small tris for below) is 36 * 51 divided by 2 (area of triangle is base * height over 2). this would give you 918.
area of the small triangle below is 51 * 11 divided by 2 (see above), which is 280.5.
shaded shape area is the big triangle shape minus the small triangle below, which is 918-270.5, which is 637.5 units.
Answer:

Step-by-step explanation:
Notice how each congruent square is divided into four equal parts. Since each square has four parts and there are four squares, there are
of these parts in total. Because each of these parts make up
of each square, all parts are equal. Therefore, you can count the total number of shaded parts to get your percentage.
The top left and bottom right both have one part shaded each for a total of
parts.
The top right and bottom left have
and
parts shaded, respectively, for a total of
parts.
Therefore, in total, there are
parts shaded out of
total parts.
Thus, the percentage of the total area that is shaded is:
.