Answer:
0
Step-by-step explanation:
0 is a whole number but not a natural number because it does not have a positive or negative value.
Answer:
20,7,13. are the most correct for a triangular shape
Answer:

Step By Step Explanation:
Apply Rule - (-a) = a

Multiply: 4 · 6 = 24

Expand 
= 
Simplify 
= 
━ Mordancy ━
Answer:
No they don't form a proportion
Step-by-step explanation:
Their denominatiors do not share a common multiple, therefore they can not form a proportion.