Finding the Fourth Proportional to 1,920.79, 2,881.59 and 688.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,920.79 : 2,881.59 = 688.15 : x
2. Step 2: Convert to fraction form
   1,920.79/2,881.59 = 688.15/x
3. Step 3: Cross multiply
   1,920.79x = 2,881.59 × 688.15
4. Step 4: Simplify right side
   1,920.79x = 1,982,966.16
5. Step 5: Solve for x
   x = 1,982,966.16/1,920.79
6. Step 6: Final answer
   x = 1,032.37