Finding the Fourth Proportional to 2,109.78, 3,161.18 and 1,285.56

Step by Step Solution

1. Step 1: Write the proportion equation
   2,109.78 : 3,161.18 = 1,285.56 : x
2. Step 2: Convert to fraction form
   2,109.78/3,161.18 = 1,285.56/x
3. Step 3: Cross multiply
   2,109.78x = 3,161.18 × 1,285.56
4. Step 4: Simplify right side
   2,109.78x = 4,063,886.56
5. Step 5: Solve for x
   x = 4,063,886.56/2,109.78
6. Step 6: Final answer
   x = 1,926.21