Finding the Fourth Proportional to 2,660.09, 3,990.16 and 928.72

Step by Step Solution

1. Step 1: Write the proportion equation
   2,660.09 : 3,990.16 = 928.72 : x
2. Step 2: Convert to fraction form
   2,660.09/3,990.16 = 928.72/x
3. Step 3: Cross multiply
   2,660.09x = 3,990.16 × 928.72
4. Step 4: Simplify right side
   2,660.09x = 3,705,741.40
5. Step 5: Solve for x
   x = 3,705,741.40/2,660.09
6. Step 6: Final answer
   x = 1,393.09