Finding the Fourth Proportional to 3,700.10, 5,105.90 and 2,128.20

Step by Step Solution

1. Step 1: Write the proportion equation
   3,700.10 : 5,105.90 = 2,128.20 : x
2. Step 2: Convert to fraction form
   3,700.10/5,105.90 = 2,128.20/x
3. Step 3: Cross multiply
   3,700.10x = 5,105.90 × 2,128.20
4. Step 4: Simplify right side
   3,700.10x = 10,866,376.38
5. Step 5: Solve for x
   x = 10,866,376.38/3,700.10
6. Step 6: Final answer
   x = 2,936.78