Finding the Fourth Proportional to 1,287.33, 1,929.91 and 875.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,287.33 : 1,929.91 = 875.31 : x
2. Step 2: Convert to fraction form
   1,287.33/1,929.91 = 875.31/x
3. Step 3: Cross multiply
   1,287.33x = 1,929.91 × 875.31
4. Step 4: Simplify right side
   1,287.33x = 1,689,269.52
5. Step 5: Solve for x
   x = 1,689,269.52/1,287.33
6. Step 6: Final answer
   x = 1,312.23