Geometry
[tex] {a}^{2} + {b}^{2} = {c}^{2} [/tex]
Input the lengths already known.
[tex] {16}^{2} + {b}^{2} = {20}^{2} [/tex]
Simplify 16^2 and 20^2.
[tex]256 + {b}^{2} = 400[/tex]
Subtract 256 from both sides.
[tex] {b}^{2} = 144[/tex]
[tex]b = \sqrt{144} [/tex]
Meaning, b=12