Finding the Fourth Proportional to 5,391.50, 7,428.51 and 3,972.78

Step by Step Solution

1. Step 1: Write the proportion equation
   5,391.50 : 7,428.51 = 3,972.78 : x
2. Step 2: Convert to fraction form
   5,391.50/7,428.51 = 3,972.78/x
3. Step 3: Cross multiply
   5,391.50x = 7,428.51 × 3,972.78
4. Step 4: Simplify right side
   5,391.50x = 29,511,835.96
5. Step 5: Solve for x
   x = 29,511,835.96/5,391.50
6. Step 6: Final answer
   x = 5,473.78