Finding the Fourth Proportional to 12,978.36, 17,910.90 and 7,671.96

Step by Step Solution

1. Step 1: Write the proportion equation
   12,978.36 : 17,910.90 = 7,671.96 : x
2. Step 2: Convert to fraction form
   12,978.36/17,910.90 = 7,671.96/x
3. Step 3: Cross multiply
   12,978.36x = 17,910.90 × 7,671.96
4. Step 4: Simplify right side
   12,978.36x = 137,411,708.36
5. Step 5: Solve for x
   x = 137,411,708.36/12,978.36
6. Step 6: Final answer
   x = 10,587.76