Finding the Fourth Proportional to 12,978, 17,910.72 and 7,390.08

Step by Step Solution

1. Step 1: Write the proportion equation
   12,978 : 17,910.72 = 7,390.08 : x
2. Step 2: Convert to fraction form
   12,978/17,910.72 = 7,390.08/x
3. Step 3: Cross multiply
   12,978x = 17,910.72 × 7,390.08
4. Step 4: Simplify right side
   12,978x = 132,361,653.66
5. Step 5: Solve for x
   x = 132,361,653.66/12,978
6. Step 6: Final answer
   x = 10,198.93