Answer: 3[tex]\sqrt{5}[/tex]
Step-by-step explanation:
as you see c is the hypotenuse of the triangle that has two of the side 6 and 3
c^2=a^+b^2
c^2= 3^2+6^2
c^2=9+36
c^2=45
c= [tex]\sqrt{45}[/tex]=3[tex]\sqrt{5}[/tex]