Finding the Fourth Proportional to 28,259.40, 42,389.42 and 8,538.12

Step by Step Solution

1. Step 1: Write the proportion equation
   28,259.40 : 42,389.42 = 8,538.12 : x
2. Step 2: Convert to fraction form
   28,259.40/42,389.42 = 8,538.12/x
3. Step 3: Cross multiply
   28,259.40x = 42,389.42 × 8,538.12
4. Step 4: Simplify right side
   28,259.40x = 361,925,954.69
5. Step 5: Solve for x
   x = 361,925,954.69/28,259.40
6. Step 6: Final answer
   x = 12,807.28