Finding the Fourth Proportional to 8,978.28, 12,389.70 and 5,252.20

Step by Step Solution

1. Step 1: Write the proportion equation
   8,978.28 : 12,389.70 = 5,252.20 : x
2. Step 2: Convert to fraction form
   8,978.28/12,389.70 = 5,252.20/x
3. Step 3: Cross multiply
   8,978.28x = 12,389.70 × 5,252.20
4. Step 4: Simplify right side
   8,978.28x = 65,073,182.34
5. Step 5: Solve for x
   x = 65,073,182.34/8,978.28
6. Step 6: Final answer
   x = 7,247.85