Finding the Fourth Proportional to 1,398.72, 2,088.24 and 1,155.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,398.72 : 2,088.24 = 1,155.72 : x
2. Step 2: Convert to fraction form
   1,398.72/2,088.24 = 1,155.72/x
3. Step 3: Cross multiply
   1,398.72x = 2,088.24 × 1,155.72
4. Step 4: Simplify right side
   1,398.72x = 2,413,420.73
5. Step 5: Solve for x
   x = 2,413,420.73/1,398.72
6. Step 6: Final answer
   x = 1,725.45