Answer:
12
Step-by-step explanation:
There is a right angle formed, hence this triangle is a right-angled triangle.
Using Pythagoras Theorem,
[tex]a^2+b^2=c^2[/tex]
[tex]16^2+b^2=20^2[/tex]
[tex]256+b^2=400[/tex]
[tex]b^2=400-256=144[/tex]
[tex]b=12[/tex]
The missing length is 12
