Finding the Fourth Proportional to 23,128.20, 31,917.03 and 13,057.05

Step by Step Solution

1. Step 1: Write the proportion equation
   23,128.20 : 31,917.03 = 13,057.05 : x
2. Step 2: Convert to fraction form
   23,128.20/31,917.03 = 13,057.05/x
3. Step 3: Cross multiply
   23,128.20x = 31,917.03 × 13,057.05
4. Step 4: Simplify right side
   23,128.20x = 416,742,256.56
5. Step 5: Solve for x
   x = 416,742,256.56/23,128.20
6. Step 6: Final answer
   x = 18,018.79