Answer:
The only grouping that is a true proportion is B.
Step-by-step explanation:
To tell if two are proportional, simply multiply the numerator from the first by the denominator of the second. Then multiply the denominator from the first and the numerator for the second. If the two products are the same, then it is proportional.
B) 4/12 = 6/18
4*18 = 12 * 6
72 = 72
Do you have the rest of the question?
Answer:

Step-by-step explanation:
Multiply across.

Then Simplify.

Answer:
4
Step-by-step explanation:
The diagonals are equal length:


Answer:
5
Step-by-step explanation:
5