Finding the Fourth Proportional to 10,978.20, 15,155.91 and 7,580.25

Step by Step Solution

1. Step 1: Write the proportion equation
   10,978.20 : 15,155.91 = 7,580.25 : x
2. Step 2: Convert to fraction form
   10,978.20/15,155.91 = 7,580.25/x
3. Step 3: Cross multiply
   10,978.20x = 15,155.91 × 7,580.25
4. Step 4: Simplify right side
   10,978.20x = 114,885,586.78
5. Step 5: Solve for x
   x = 114,885,586.78/10,978.20
6. Step 6: Final answer
   x = 10,464.88