Finding the Fourth Proportional to 1,542.31, 2,128.83 and 879.60

Step by Step Solution

1. Step 1: Write the proportion equation
   1,542.31 : 2,128.83 = 879.60 : x
2. Step 2: Convert to fraction form
   1,542.31/2,128.83 = 879.60/x
3. Step 3: Cross multiply
   1,542.31x = 2,128.83 × 879.60
4. Step 4: Simplify right side
   1,542.31x = 1,872,518.87
5. Step 5: Solve for x
   x = 1,872,518.87/1,542.31
6. Step 6: Final answer
   x = 1,214.10