Answer:
a = 6[tex]\sqrt{2}[/tex]
Step-by-step explanation:
[tex]a^{2}[/tex] + [tex]c^{2}[/tex] = [tex]18^{2}[/tex] (pythagoras theorem)
[tex]a^{2}[/tex] + [tex]b^{2}[/tex] = [tex]4^{2}[/tex] (pythagoras theorem)
[tex]c^{2}[/tex] + [tex]b^{2}[/tex] = [tex]22^{2}[/tex] (pythagoras theorem)
From these 3 equations we can find the value of a
