Finding the Fourth Proportional to 28,109.62, 42,165.78 and 8,389.72

Step by Step Solution

1. Step 1: Write the proportion equation
   28,109.62 : 42,165.78 = 8,389.72 : x
2. Step 2: Convert to fraction form
   28,109.62/42,165.78 = 8,389.72/x
3. Step 3: Cross multiply
   28,109.62x = 42,165.78 × 8,389.72
4. Step 4: Simplify right side
   28,109.62x = 353,759,087.78
5. Step 5: Solve for x
   x = 353,759,087.78/28,109.62
6. Step 6: Final answer
   x = 12,584.98