Finding the Fourth Proportional to 2,100.86, 3,155.87 and 1,805.61

Step by Step Solution

1. Step 1: Write the proportion equation
   2,100.86 : 3,155.87 = 1,805.61 : x
2. Step 2: Convert to fraction form
   2,100.86/3,155.87 = 1,805.61/x
3. Step 3: Cross multiply
   2,100.86x = 3,155.87 × 1,805.61
4. Step 4: Simplify right side
   2,100.86x = 5,698,274.94
5. Step 5: Solve for x
   x = 5,698,274.94/2,100.86
6. Step 6: Final answer
   x = 2,712.36