Finding the Fourth Proportional to 2,661.40, 3,991.86 and 929.92

Step by Step Solution

1. Step 1: Write the proportion equation
   2,661.40 : 3,991.86 = 929.92 : x
2. Step 2: Convert to fraction form
   2,661.40/3,991.86 = 929.92/x
3. Step 3: Cross multiply
   2,661.40x = 3,991.86 × 929.92
4. Step 4: Simplify right side
   2,661.40x = 3,712,110.45
5. Step 5: Solve for x
   x = 3,712,110.45/2,661.40
6. Step 6: Final answer
   x = 1,394.80