Finding the Fourth Proportional to 1,921.77, 2,881.89 and 688.80

Step by Step Solution

1. Step 1: Write the proportion equation
   1,921.77 : 2,881.89 = 688.80 : x
2. Step 2: Convert to fraction form
   1,921.77/2,881.89 = 688.80/x
3. Step 3: Cross multiply
   1,921.77x = 2,881.89 × 688.80
4. Step 4: Simplify right side
   1,921.77x = 1,985,045.83
5. Step 5: Solve for x
   x = 1,985,045.83/1,921.77
6. Step 6: Final answer
   x = 1,032.93