Finding the Fourth Proportional to 1,081.61, 1,492.40 and 688.49

Step by Step Solution

1. Step 1: Write the proportion equation
   1,081.61 : 1,492.40 = 688.49 : x
2. Step 2: Convert to fraction form
   1,081.61/1,492.40 = 688.49/x
3. Step 3: Cross multiply
   1,081.61x = 1,492.40 × 688.49
4. Step 4: Simplify right side
   1,081.61x = 1,027,498.46
5. Step 5: Solve for x
   x = 1,027,498.46/1,081.61
6. Step 6: Final answer
   x = 949.97