Finding the Fourth Proportional to 12,978.07, 17,911.07 and 7,945.62

Step by Step Solution

1. Step 1: Write the proportion equation
   12,978.07 : 17,911.07 = 7,945.62 : x
2. Step 2: Convert to fraction form
   12,978.07/17,911.07 = 7,945.62/x
3. Step 3: Cross multiply
   12,978.07x = 17,911.07 × 7,945.62
4. Step 4: Simplify right side
   12,978.07x = 142,314,556.01
5. Step 5: Solve for x
   x = 142,314,556.01/12,978.07
6. Step 6: Final answer
   x = 10,965.77