Finding the Fourth Proportional to 9,890.15, 13,647.72 and 5,641.40

Step by Step Solution

1. Step 1: Write the proportion equation
   9,890.15 : 13,647.72 = 5,641.40 : x
2. Step 2: Convert to fraction form
   9,890.15/13,647.72 = 5,641.40/x
3. Step 3: Cross multiply
   9,890.15x = 13,647.72 × 5,641.40
4. Step 4: Simplify right side
   9,890.15x = 76,992,179.37
5. Step 5: Solve for x
   x = 76,992,179.37/9,890.15
6. Step 6: Final answer
   x = 7,784.73