Finding the Fourth Proportional to 12,928, 19,381.68 and 5,134.72

Step by Step Solution

1. Step 1: Write the proportion equation
   12,928 : 19,381.68 = 5,134.72 : x
2. Step 2: Convert to fraction form
   12,928/19,381.68 = 5,134.72/x
3. Step 3: Cross multiply
   12,928x = 19,381.68 × 5,134.72
4. Step 4: Simplify right side
   12,928x = 99,519,499.93
5. Step 5: Solve for x
   x = 99,519,499.93/12,928
6. Step 6: Final answer
   x = 7,697.98