Answer:
3/12 = 1/4
Step-by-step explanation:
There are 12 marbles in the bag. If the marble drawn at random is red, it is one of the 3 red marbles.
The probability is "3 out of 12" = 3/12 which simplifies to 1/4.
So when you have data given this kind of form... you should convert to decimal first.
So that would be:
a ≈ 2.12
b = 3.5
c = 2.5
Now just place the simple perimeter formula, and sum all sides.