Finding the Fourth Proportional to 1,407.04, 2,105.76 and 858.88

Step by Step Solution

1. Step 1: Write the proportion equation
   1,407.04 : 2,105.76 = 858.88 : x
2. Step 2: Convert to fraction form
   1,407.04/2,105.76 = 858.88/x
3. Step 3: Cross multiply
   1,407.04x = 2,105.76 × 858.88
4. Step 4: Simplify right side
   1,407.04x = 1,808,595.15
5. Step 5: Solve for x
   x = 1,808,595.15/1,407.04
6. Step 6: Final answer
   x = 1,285.39