Answer:
![|SU|=√(13)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/iloelv4yve9ynwzeduvaoomoronks1he4i.png)
Explanation:
The given parallelogram has vertices R(1, -1), S(6, 1), T(8, 5), and U(3, 3) .
Recall the distance formula;
We use the distance formula to determine the length of the diagonals.
For diagonal R(1,-1) and T(8,5), We have;
![|RT|=√((8-1)^2+(5--1)^2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/6imktcfk6955407f1820g56r2e9tttnet1.png)
![|RT|=√((7)^2+(6)^2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/qq5n61n4tkw420ubod4euvujzjelnpvucq.png)
![|RT|=√(49+36)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/r51xubdr5wt0o3tnl91es3bs1yy8zk2zlc.png)
![|RT|=√(85)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/wbls5t4kwjzkxq5nsff96lyxxx5bmwjcr1.png)
For the diagonal S(6,1) U(3,3)
![|SU|=√((6-3)^2+(5-3)^2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/mi4cnw4jokncv4ax7d5m8jb5ky5vkhdijp.png)
![|SU|=√((3)^2+(2)^2)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/2fbkmvyhv45elj0zlz8ocdzxqdtkj4pogq.png)
![|SU|=√(9+4)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/350idcnqauqopomb33qg9dwuerzvbugel1.png)
![|SU|=√(13)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/iloelv4yve9ynwzeduvaoomoronks1he4i.png)
Therefore the shorter diagonal is:
![|SU|=√(13)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/iloelv4yve9ynwzeduvaoomoronks1he4i.png)