Finding the Fourth Proportional to 2,086.06, 3,129.15 and 931.90

Step by Step Solution

1. Step 1: Write the proportion equation
   2,086.06 : 3,129.15 = 931.90 : x
2. Step 2: Convert to fraction form
   2,086.06/3,129.15 = 931.90/x
3. Step 3: Cross multiply
   2,086.06x = 3,129.15 × 931.90
4. Step 4: Simplify right side
   2,086.06x = 2,916,054.89
5. Step 5: Solve for x
   x = 2,916,054.89/2,086.06
6. Step 6: Final answer
   x = 1,397.88