Finding the Fourth Proportional to 9,856.76, 13,602.40 and 5,380.55

Step by Step Solution

1. Step 1: Write the proportion equation
   9,856.76 : 13,602.40 = 5,380.55 : x
2. Step 2: Convert to fraction form
   9,856.76/13,602.40 = 5,380.55/x
3. Step 3: Cross multiply
   9,856.76x = 13,602.40 × 5,380.55
4. Step 4: Simplify right side
   9,856.76x = 73,188,393.32
5. Step 5: Solve for x
   x = 73,188,393.32/9,856.76
6. Step 6: Final answer
   x = 7,425.20