Finding the Fourth Proportional to 10,115.20, 13,959.24 and 5,638.72

Step by Step Solution

1. Step 1: Write the proportion equation
   10,115.20 : 13,959.24 = 5,638.72 : x
2. Step 2: Convert to fraction form
   10,115.20/13,959.24 = 5,638.72/x
3. Step 3: Cross multiply
   10,115.20x = 13,959.24 × 5,638.72
4. Step 4: Simplify right side
   10,115.20x = 78,712,245.77
5. Step 5: Solve for x
   x = 78,712,245.77/10,115.20
6. Step 6: Final answer
   x = 7,781.58