Finding the Fourth Proportional to 20,139.12, 30,190.56 and 7,656.72

Step by Step Solution

1. Step 1: Write the proportion equation
   20,139.12 : 30,190.56 = 7,656.72 : x
2. Step 2: Convert to fraction form
   20,139.12/30,190.56 = 7,656.72/x
3. Step 3: Cross multiply
   20,139.12x = 30,190.56 × 7,656.72
4. Step 4: Simplify right side
   20,139.12x = 231,160,664.56
5. Step 5: Solve for x
   x = 231,160,664.56/20,139.12
6. Step 6: Final answer
   x = 11,478.19