Finding the Fourth Proportional to 9,913.56, 13,680.60 and 5,721.72

Step by Step Solution

1. Step 1: Write the proportion equation
   9,913.56 : 13,680.60 = 5,721.72 : x
2. Step 2: Convert to fraction form
   9,913.56/13,680.60 = 5,721.72/x
3. Step 3: Cross multiply
   9,913.56x = 13,680.60 × 5,721.72
4. Step 4: Simplify right side
   9,913.56x = 78,276,562.63
5. Step 5: Solve for x
   x = 78,276,562.63/9,913.56
6. Step 6: Final answer
   x = 7,895.91