First, we need to find the sides of the triangle.
The base of the triangles is 8ft - 5ft = 3ft.
The height for the triangle is 7ft - 4ft = 3ft
Now, we need to find the area of the triangle:
![A_t=(base\cdot height)/(2)](https://img.qammunity.org/2023/formulas/mathematics/college/ve25wr6zp1m4la593be7to99okaw1taobb.png)
Replacing the values:
![A_t=(3ft\cdot3ft)/(2)](https://img.qammunity.org/2023/formulas/mathematics/college/nr4snjimgqygwvrgxkphebyui0s2mx1p7o.png)
Then
![A_t=4.5ft^2^{}](https://img.qammunity.org/2023/formulas/mathematics/college/t3az2zt3f1ewojeok021riwk1zvt90zcho.png)
Now, we need to find the area for the rectangle:
Area for a rectangle = Length * Width
In this case:
Length = 8ft
Width = 7ft
Therefore:
![A_r=8ft\cdot7ft](https://img.qammunity.org/2023/formulas/mathematics/college/msmxn1l5emjfltj5fhk8gatkb4lcpai7b7.png)
Then
![A_r=56](https://img.qammunity.org/2023/formulas/mathematics/college/dcj1lw5qahi8ukxlnoxdujos1x81dju79d.png)
Finally, to find the area of the shaded region we need to subtract the triangle area from the rectangle area:
![A=A_r-A_t](https://img.qammunity.org/2023/formulas/mathematics/college/t350b5cs07tfrz4up0dk56qni3o2oly8jm.png)
Therefore:
![A=56ft^2-4.5ft^2](https://img.qammunity.org/2023/formulas/mathematics/college/i44wa2bzt264wqx197bqctu15eay60dom6.png)
![A=51.5ft^2](https://img.qammunity.org/2023/formulas/mathematics/college/4i7l8zaz93rke4uubcramfer2k9zssv3en.png)
Hence, the area for the shaded region is 51.5 ft².