Finding the Fourth Proportional to 9,889.10, 13,646.90 and 5,412.78

Step by Step Solution

1. Step 1: Write the proportion equation
   9,889.10 : 13,646.90 = 5,412.78 : x
2. Step 2: Convert to fraction form
   9,889.10/13,646.90 = 5,412.78/x
3. Step 3: Cross multiply
   9,889.10x = 13,646.90 × 5,412.78
4. Step 4: Simplify right side
   9,889.10x = 73,867,667.38
5. Step 5: Solve for x
   x = 73,867,667.38/9,889.10
6. Step 6: Final answer
   x = 7,469.60