If the perimeter is 20 what must be the length of the missing side length? (Answer with Number Only) *

Answer:
8
Step-by-step explanation:
Perimeter = Sum of all side lengths
If perimeter = 20, then 5 + 3 + 4 + x = 20
( where x = missing side length )
5 + 3 + 4 = 12
12 + x = 20
20 - 12 = 8
Hence, x = 8