Solution
Step 1
Consider the triangle with 2 known sides to find the value of the third side
Using Pythagoras theorem
[tex]\begin{gathered} (3^{rd}side)^2=4^2+2^2 \\ 3^{rd\text{ }}Side\text{ = }\sqrt[]{16\text{ +4}} \\ 3^{rd}Side\text{ = }\sqrt[]{20}=2\sqrt[]{5} \end{gathered}[/tex]
Step 2
Use the third known side with the second triangle to find the value of x
[tex]\begin{gathered} x^2=5^2-(2\sqrt[]{5)^2} \\ x=\sqrt[]{25-20} \\ x\text{ =}\sqrt[]{5} \end{gathered}[/tex]
x, therefore, = √5 in the simplest radical form
