Finding the Fourth Proportional to 13,978.56, 19,289.68 and 7,689.72

Step by Step Solution

1. Step 1: Write the proportion equation
   13,978.56 : 19,289.68 = 7,689.72 : x
2. Step 2: Convert to fraction form
   13,978.56/19,289.68 = 7,689.72/x
3. Step 3: Cross multiply
   13,978.56x = 19,289.68 × 7,689.72
4. Step 4: Simplify right side
   13,978.56x = 148,332,238.09
5. Step 5: Solve for x
   x = 148,332,238.09/13,978.56
6. Step 6: Final answer
   x = 10,611.41