Finding the Fourth Proportional to 9,856.62, 13,601.86 and 5,380.40

Step by Step Solution

1. Step 1: Write the proportion equation
   9,856.62 : 13,601.86 = 5,380.40 : x
2. Step 2: Convert to fraction form
   9,856.62/13,601.86 = 5,380.40/x
3. Step 3: Cross multiply
   9,856.62x = 13,601.86 × 5,380.40
4. Step 4: Simplify right side
   9,856.62x = 73,183,468.10
5. Step 5: Solve for x
   x = 73,183,468.10/9,856.62
6. Step 6: Final answer
   x = 7,424.80