Finding the Fourth Proportional to 1,403.85, 2,105.82 and 430.05

Step by Step Solution

1. Step 1: Write the proportion equation
   1,403.85 : 2,105.82 = 430.05 : x
2. Step 2: Convert to fraction form
   1,403.85/2,105.82 = 430.05/x
3. Step 3: Cross multiply
   1,403.85x = 2,105.82 × 430.05
4. Step 4: Simplify right side
   1,403.85x = 905,607.89
5. Step 5: Solve for x
   x = 905,607.89/1,403.85
6. Step 6: Final answer
   x = 645.09