Finding the Fourth Proportional to 8,538.29, 12,875.73 and 8,421.42

Step by Step Solution

1. Step 1: Write the proportion equation
   8,538.29 : 12,875.73 = 8,421.42 : x
2. Step 2: Convert to fraction form
   8,538.29/12,875.73 = 8,421.42/x
3. Step 3: Cross multiply
   8,538.29x = 12,875.73 × 8,421.42
4. Step 4: Simplify right side
   8,538.29x = 108,431,945.47
5. Step 5: Solve for x
   x = 108,431,945.47/8,538.29
6. Step 6: Final answer
   x = 12,699.50