Answer:
55%
Step-by-step explanation:
Since the perimeter of the square is 40, its side length is 40/4 = 10, so its area is 100.
To find the percentage of the shaded area, I am going to find the unshaded areas, which consist of 2 triangles.
The one on the left has lengths of 10(side length of the square) and 3(10-7), which means it has an area of 10*3/2 = 15.
The one on the right has lengths of 10(side length of the square) and 6(10-4), which means it has an area of 10*6/2 = 30.
That means the unshaded area is 15+30 = 45.
To find the shaded area, just subtract 45(unshaded area) from 100(area of square), which is 55 cm^2.
55 cm^2 is exactly 55% of 100, so the answer is 55%.
I hope this helped you.
