Answer:
The answer is B.
Explanation:
You have to use Pythogorean Theorem, c² = a² + b² where c is the hypotenuse and a,b is the side lengths :
![{c}^(2) = {a}^(2) + {b}^(2)](https://img.qammunity.org/2021/formulas/mathematics/high-school/s4mafuaojr84ezwris8vazuajbl2wwdibj.png)
Let a = 40,
Let b = 9,
![{c}^(2) = {40}^(2) + {9}^(2)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/s5b8eftsdens24hqgt0vr5cm3dqbn2dbw0.png)
![{c}^(2) = 1600 + 81](https://img.qammunity.org/2021/formulas/mathematics/middle-school/t2z1snjsiciduea4dsid8i688gysi2aw33.png)
![{c}^(2) = 1681](https://img.qammunity.org/2021/formulas/mathematics/middle-school/zu9pizlcruxtf7j6jbpzjfs67r7057j1xu.png)
![c = √(1681)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/gurlv30eqezznsomxwfanky0x4ze19gwvd.png)
![c = 41 \: units](https://img.qammunity.org/2021/formulas/mathematics/middle-school/pz810bvikux6zx2ixsqzj5wkxamrixx1oc.png)
*Take note, hypotenuse will always be the longest length among the 3 lengths.
*Pythogorean Theorem can only applied in a right-angle triangle.