Any help? its the Pythagorean Theorem

Answer:
x = [tex]\sqrt{13}[/tex] or 3.61 to 3 significant figures
Step-by-step explanation:
First find CD which is [tex]\sqrt{5^{2}-3^{2} }[/tex] = 4
6 - 4 = 2 which is FC
so do [tex]\sqrt{2^{2}+3^{2} }[/tex] = [tex]\sqrt{13}[/tex] or 3.61 to 3 significant figures