CAN SOMEONE HELP SO I DONT FAILLLLL

Answer:
2[tex]\sqrt{22}[/tex]
Step-by-step explanation:
Use pythagorus's theorem:
a²=b²+c²
13²=9²+x²
169=81+x²
x²=88
x=[tex]\sqrt{88}[/tex]
x=[tex]\sqrt{22*4}[/tex]
x=[tex]\sqrt{22} \sqrt{4}[/tex]
x=2[tex]\sqrt{22}[/tex]