Answer: The fourth set of sides
Explanation:
For a set of side lengths to form a right triangle, they have to satisfy the Pythagorean theory
![(a^(2) +b^(2) =c^(2) )](https://img.qammunity.org/2022/formulas/mathematics/high-school/d0klmyhycaov486qzg8a16xdtvaue1sulu.png)
First set of sides
a = 7.5 b = 18 c = 21.5
![a^(2) +b^(2) =c^(2)\\7.5^(2) +18^(2) =21.5^(2) \\56.25 + 324 = 462.25\\380.25 \\eq 462.25](https://img.qammunity.org/2022/formulas/mathematics/high-school/vlibhemoanll5l41xqx7fmke3sjpgxcan7.png)
Second set of sides
a = 7.5 b = 19.5 c = 21.5
![a^(2) +b^(2) =c^(2) \\7.5^(2) +19.5^(2) =21.5^(2) \\56.25 + 380.25 = 462.25\\436.5 \\eq 462.25](https://img.qammunity.org/2022/formulas/mathematics/high-school/de16655wd9fjl2edjuac1ivc7b2sysga7p.png)
Third set of sides
a = 18 b = 19.25 c = 21.5
![a^(2) +b^(2) =c^(2) \\18^(2) +19.5^(2) =21.5^(2) \\324 + 380.25 = 462.25\\704.25 \\eq 462.25](https://img.qammunity.org/2022/formulas/mathematics/high-school/3e02oyaiiaqhwaks2856mqs48k2looyjcw.png)
Fourth set of sides
a = 7.5 b = 18 c = 19.5
![a^(2) +b^(2) =c^(2) \\7.5^(2) +18^(2) =19.5^(2) \\56.25 + 324 = 380.25\\380.25 = 380.25](https://img.qammunity.org/2022/formulas/mathematics/high-school/5dogw4pq3bffxctktmghhklbothvyrtzvd.png)
I hope that helped!