Answer:
![50√(2) feet](https://img.qammunity.org/2021/formulas/mathematics/college/jxa16qrns0woqhc9va9uvm4zr8ylr9cq7r.png)
Explanation:
Given the vertices (1, 5) and (11, 15) for the corners labeled with red stars, the diagonal of the square C will be the length of the line joining the two vertices.
Using the Distance Formula:
![Distance=√((x_2-x_1)^2+(y_2-y_1)^2)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/y4m7yqgt8t3avbuucywckv67ewv4swgsq7.png)
![(x_1,y_1)=(1, 5) \:and\: (x_2,y_2)=(11, 15)](https://img.qammunity.org/2021/formulas/mathematics/college/irltv80swsemj1snkhmivnc7zk7w9sg17l.png)
![Distance=√((11-1)^2+(15-5)^2)\\=√(10^2+10^2)\\=√(200)\\=10√(2)](https://img.qammunity.org/2021/formulas/mathematics/college/4b7hoqihtz8lfz0ebxj6f7v04pj2dm6q5p.png)
Since 1 Square Unit = 25 Square Feet
1 Unit =5 feet
Therefore, the length of the diagonal
![=5*10√(2) \\=50√(2) \:feet](https://img.qammunity.org/2021/formulas/mathematics/college/5htf02auvoftixx5vnp3zkzhmurvuq8bh6.png)