Step-by-step explanation:
As a square with a perimeter of 40cm.
It means each side of the square has a length 10cm.
i.e.
P = 10+10+10+10
= 40cm
and
The total Area of the diagram of square = 10 × 10 = 100 cm²
Calculating the Shaded Area:
As the upper length of shaded side of the shape inside square = 7 cm
so the non-shaded length of upper side of the square = 10-7 = 3cm
so
the area of left sided un-shaded triangle = 1/2 * b * h
= (3 * 10)/2
Similarly, the right sided length of shaded side inside the square = 4 cm
so the non-shaded right sided-length of the square = 10-4 = 6cm
the area of right sided un-shaded triangle = 1/2 * b * h
= (10 * 6)/2
Therefore, the area inside the square that is shaded is:
[tex]\left(10\:\times 10\right)\:-\:\frac{\left(3\:\times \:10\right)}{2}\:-\:\frac{\left(10\times \:6\right)}{2}[/tex]
[tex]=\left(10\times \:10\right)-45[/tex] ∵ [tex]-\frac{3\times \:10}{2}-\frac{10\times \:6}{2}:\quad -45[/tex]
[tex]=100-45[/tex]
[tex]=55[/tex] cm²
So, the percentage of the total area inside the square
that is shaded = 55%.
And the percentage of the total area inside the square
that is non-shaded = 100 - 55 = 45 cm² ∵ Total Area - shaded Area
Therefore, the percentage of the total area inside the square
that is shaded = 55%.
