Finding the Fourth Proportional to 8,267.42, 12,387.89 and 7,428.15

Step by Step Solution

1. Step 1: Write the proportion equation
   8,267.42 : 12,387.89 = 7,428.15 : x
2. Step 2: Convert to fraction form
   8,267.42/12,387.89 = 7,428.15/x
3. Step 3: Cross multiply
   8,267.42x = 12,387.89 × 7,428.15
4. Step 4: Simplify right side
   8,267.42x = 92,019,123.67
5. Step 5: Solve for x
   x = 92,019,123.67/8,267.42
6. Step 6: Final answer
   x = 11,130.33