Finding the Fourth Proportional to 5,156.56, 7,672.80 and 5,139.28

Step by Step Solution

1. Step 1: Write the proportion equation
   5,156.56 : 7,672.80 = 5,139.28 : x
2. Step 2: Convert to fraction form
   5,156.56/7,672.80 = 5,139.28/x
3. Step 3: Cross multiply
   5,156.56x = 7,672.80 × 5,139.28
4. Step 4: Simplify right side
   5,156.56x = 39,432,667.58
5. Step 5: Solve for x
   x = 39,432,667.58/5,156.56
6. Step 6: Final answer
   x = 7,647.09