Finding the Fourth Proportional to 1,390.05, 1,917.54 and 1,127.61

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.05 : 1,917.54 = 1,127.61 : x
2. Step 2: Convert to fraction form
   1,390.05/1,917.54 = 1,127.61/x
3. Step 3: Cross multiply
   1,390.05x = 1,917.54 × 1,127.61
4. Step 4: Simplify right side
   1,390.05x = 2,162,237.28
5. Step 5: Solve for x
   x = 2,162,237.28/1,390.05
6. Step 6: Final answer
   x = 1,555.51