Finding the Fourth Proportional to 9,886.42, 13,643.17 and 5,638.15

Step by Step Solution

1. Step 1: Write the proportion equation
   9,886.42 : 13,643.17 = 5,638.15 : x
2. Step 2: Convert to fraction form
   9,886.42/13,643.17 = 5,638.15/x
3. Step 3: Cross multiply
   9,886.42x = 13,643.17 × 5,638.15
4. Step 4: Simplify right side
   9,886.42x = 76,922,238.94
5. Step 5: Solve for x
   x = 76,922,238.94/9,886.42
6. Step 6: Final answer
   x = 7,780.60