Finding the Fourth Proportional to 8,499.43, 12,748.20 and 5,206.78

Step by Step Solution

1. Step 1: Write the proportion equation
   8,499.43 : 12,748.20 = 5,206.78 : x
2. Step 2: Convert to fraction form
   8,499.43/12,748.20 = 5,206.78/x
3. Step 3: Cross multiply
   8,499.43x = 12,748.20 × 5,206.78
4. Step 4: Simplify right side
   8,499.43x = 66,377,072.80
5. Step 5: Solve for x
   x = 66,377,072.80/8,499.43
6. Step 6: Final answer
   x = 7,809.59