Finding the Fourth Proportional to 13,659.78, 18,849.78 and 7,691.25

Step by Step Solution

1. Step 1: Write the proportion equation
   13,659.78 : 18,849.78 = 7,691.25 : x
2. Step 2: Convert to fraction form
   13,659.78/18,849.78 = 7,691.25/x
3. Step 3: Cross multiply
   13,659.78x = 18,849.78 × 7,691.25
4. Step 4: Simplify right side
   13,659.78x = 144,978,370.43
5. Step 5: Solve for x
   x = 144,978,370.43/13,659.78
6. Step 6: Final answer
   x = 10,613.52