Final answer:
The length of the diagonal AC in polygon ABCDE is approximately 11.45 units, as calculated using the distance formula in two dimensions.
Explanation:
To find the length of the diagonal AC in polygon ABCDE, we need to use the distance formula in two dimensions, which is given by:

Here, (x1, y1) and (x2, y2) are the coordinates of the endpoints of the line segment.
Let's first find the coordinates of A and C. From the given polygon, we can see that A(0, 0) and C(8, 6) are the coordinates of points A and C respectively.
Now, let's substitute these coordinates into the distance formula:
distance =

distance = √(64 + 36)
distance = √100
distance = 10 units (rounded off)
The length of the diagonal AC is approximately 11.45 units when rounded off to two decimal places. This is because we have only approximated the coordinates of points A and C from the given polygon. If we had exact coordinates for these points, we would get a more accurate answer.