Finding the Fourth Proportional to 1,098.61, 1,641.61 and 1,078.09

Step by Step Solution

1. Step 1: Write the proportion equation
   1,098.61 : 1,641.61 = 1,078.09 : x
2. Step 2: Convert to fraction form
   1,098.61/1,641.61 = 1,078.09/x
3. Step 3: Cross multiply
   1,098.61x = 1,641.61 × 1,078.09
4. Step 4: Simplify right side
   1,098.61x = 1,769,806.02
5. Step 5: Solve for x
   x = 1,769,806.02/1,098.61
6. Step 6: Final answer
   x = 1,610.95