Finding the Fourth Proportional to 1,397.72, 1,929.32 and 1,005.89

Step by Step Solution

1. Step 1: Write the proportion equation
   1,397.72 : 1,929.32 = 1,005.89 : x
2. Step 2: Convert to fraction form
   1,397.72/1,929.32 = 1,005.89/x
3. Step 3: Cross multiply
   1,397.72x = 1,929.32 × 1,005.89
4. Step 4: Simplify right side
   1,397.72x = 1,940,669.02
5. Step 5: Solve for x
   x = 1,940,669.02/1,397.72
6. Step 6: Final answer
   x = 1,388.46