Finding the Fourth Proportional to 9,888.16, 13,644.72 and 5,638.72

Step by Step Solution

1. Step 1: Write the proportion equation
   9,888.16 : 13,644.72 = 5,638.72 : x
2. Step 2: Convert to fraction form
   9,888.16/13,644.72 = 5,638.72/x
3. Step 3: Cross multiply
   9,888.16x = 13,644.72 × 5,638.72
4. Step 4: Simplify right side
   9,888.16x = 76,938,755.56
5. Step 5: Solve for x
   x = 76,938,755.56/9,888.16
6. Step 6: Final answer
   x = 7,780.90