Finding the Fourth Proportional to 1,098.77, 1,648.76 and 660.15

Step by Step Solution

1. Step 1: Write the proportion equation
   1,098.77 : 1,648.76 = 660.15 : x
2. Step 2: Convert to fraction form
   1,098.77/1,648.76 = 660.15/x
3. Step 3: Cross multiply
   1,098.77x = 1,648.76 × 660.15
4. Step 4: Simplify right side
   1,098.77x = 1,088,425.61
5. Step 5: Solve for x
   x = 1,088,425.61/1,098.77
6. Step 6: Final answer
   x = 990.59