Finding the Fourth Proportional to 2,109.18, 3,158.10 and 1,285.80

Step by Step Solution

1. Step 1: Write the proportion equation
   2,109.18 : 3,158.10 = 1,285.80 : x
2. Step 2: Convert to fraction form
   2,109.18/3,158.10 = 1,285.80/x
3. Step 3: Cross multiply
   2,109.18x = 3,158.10 × 1,285.80
4. Step 4: Simplify right side
   2,109.18x = 4,060,684.98
5. Step 5: Solve for x
   x = 4,060,684.98/2,109.18
6. Step 6: Final answer
   x = 1,925.24