Finding the Fourth Proportional to 3,105.10, 4,287.18 and 2,111.20

Step by Step Solution

1. Step 1: Write the proportion equation
   3,105.10 : 4,287.18 = 2,111.20 : x
2. Step 2: Convert to fraction form
   3,105.10/4,287.18 = 2,111.20/x
3. Step 3: Cross multiply
   3,105.10x = 4,287.18 × 2,111.20
4. Step 4: Simplify right side
   3,105.10x = 9,051,094.42
5. Step 5: Solve for x
   x = 9,051,094.42/3,105.10
6. Step 6: Final answer
   x = 2,914.91