Finding the Fourth Proportional to 12,978.39, 17,910.53 and 7,942.51

Step by Step Solution

1. Step 1: Write the proportion equation
   12,978.39 : 17,910.53 = 7,942.51 : x
2. Step 2: Convert to fraction form
   12,978.39/17,910.53 = 7,942.51/x
3. Step 3: Cross multiply
   12,978.39x = 17,910.53 × 7,942.51
4. Step 4: Simplify right side
   12,978.39x = 142,254,563.63
5. Step 5: Solve for x
   x = 142,254,563.63/12,978.39
6. Step 6: Final answer
   x = 10,960.88