Answer:
[tex]n=22\ units[/tex]
Step-by-step explanation:
Applying the law of cosines
[tex]c^{2}=a^{2}+b^{2}-2abcos (C)[/tex]
In this problem we have
[tex]c=n\ units[/tex]
[tex]a=20\ units[/tex]
[tex]b=9\ units[/tex]
[tex]C=90\°[/tex]
Remember that
[tex]cos(90\°)=0[/tex]
substitute
[tex]c^{2}=a^{2}+b^{2}[/tex] -----> Pythagoras Theorem, because is a right triangle
Find the value of n
[tex]n^{2}=20^{2}+9^{2}[/tex]
[tex]n^{2}=481[/tex]
[tex]n=21.93\ units[/tex]
Round to the nearest whole number
[tex]n=22\ units[/tex]
