Finding the Fourth Proportional to 2,660.56, 3,991.32 and 928.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,660.56 : 3,991.32 = 928.72 : x
2. Step 2: Convert to fraction form
   2,660.56/3,991.32 = 928.72/x
3. Step 3: Cross multiply
   2,660.56x = 3,991.32 × 928.72
4. Step 4: Simplify right side
   2,660.56x = 3,706,818.71
5. Step 5: Solve for x
   x = 3,706,818.71/2,660.56
6. Step 6: Final answer
   x = 1,393.25