A trapezoid is divided into seven strips of equal width as shown. What fraction of the trapezoid's area is shaded? Explain why your answer is correct.

![](https://cdn.mathpix.com/cropped/2024_04_17_eef89f05a2bdd3817ad8g-1.jpg?height=301&width=613&top_left_y=787&top_left_x=707)