Finding the Fourth Proportional to 12,978.03, 17,911.09 and 7,945.64

Step by Step Solution

1. Step 1: Write the proportion equation
   12,978.03 : 17,911.09 = 7,945.64 : x
2. Step 2: Convert to fraction form
   12,978.03/17,911.09 = 7,945.64/x
3. Step 3: Cross multiply
   12,978.03x = 17,911.09 × 7,945.64
4. Step 4: Simplify right side
   12,978.03x = 142,315,073.15
5. Step 5: Solve for x
   x = 142,315,073.15/12,978.03
6. Step 6: Final answer
   x = 10,965.85