Finding the Fourth Proportional to 1,391.96, 1,921.61 and 1,076.51

Step by Step Solution

1. Step 1: Write the proportion equation
   1,391.96 : 1,921.61 = 1,076.51 : x
2. Step 2: Convert to fraction form
   1,391.96/1,921.61 = 1,076.51/x
3. Step 3: Cross multiply
   1,391.96x = 1,921.61 × 1,076.51
4. Step 4: Simplify right side
   1,391.96x = 2,068,639.88
5. Step 5: Solve for x
   x = 2,068,639.88/1,391.96
6. Step 6: Final answer
   x = 1,486.13