Finding the Fourth Proportional to 1,406.88, 2,109.96 and 857.10

Step by Step Solution

1. Step 1: Write the proportion equation
   1,406.88 : 2,109.96 = 857.10 : x
2. Step 2: Convert to fraction form
   1,406.88/2,109.96 = 857.10/x
3. Step 3: Cross multiply
   1,406.88x = 2,109.96 × 857.10
4. Step 4: Simplify right side
   1,406.88x = 1,808,446.72
5. Step 5: Solve for x
   x = 1,808,446.72/1,406.88
6. Step 6: Final answer
   x = 1,285.43