The given triangle is a right angle triangle. Let x represent the missing side. We would find x by applying the pythagorean theorem which is expressed as
hypotenuse^2 = shorter leg^2 + longer leg^2
From the diagram,
hypotenuse = x
longer leg = 40
shorter leg = 9
By applying the theorem, we have
![\begin{gathered} x^2=9^2+40^2 \\ x^2\text{ = 1600 + 400 = }1681 \\ x\text{ = }\sqrt[]{1681} \\ x\text{ = }41 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/evr06hfkxtlzy5tky8z4n6qyrqg49vddr6.png)