Finding the Fourth Proportional to 10,815.78, 14,903.62 and 7,978.66

Step by Step Solution

1. Step 1: Write the proportion equation
   10,815.78 : 14,903.62 = 7,978.66 : x
2. Step 2: Convert to fraction form
   10,815.78/14,903.62 = 7,978.66/x
3. Step 3: Cross multiply
   10,815.78x = 14,903.62 × 7,978.66
4. Step 4: Simplify right side
   10,815.78x = 118,910,916.75
5. Step 5: Solve for x
   x = 118,910,916.75/10,815.78
6. Step 6: Final answer
   x = 10,994.21