Finding the Fourth Proportional to 1,403.75, 2,105.71 and 429.86

Step by Step Solution

1. Step 1: Write the proportion equation
   1,403.75 : 2,105.71 = 429.86 : x
2. Step 2: Convert to fraction form
   1,403.75/2,105.71 = 429.86/x
3. Step 3: Cross multiply
   1,403.75x = 2,105.71 × 429.86
4. Step 4: Simplify right side
   1,403.75x = 905,160.50
5. Step 5: Solve for x
   x = 905,160.50/1,403.75
6. Step 6: Final answer
   x = 644.82