Finding the Fourth Proportional to 12,178.86, 16,805.98 and 7,142.21

Step by Step Solution

1. Step 1: Write the proportion equation
   12,178.86 : 16,805.98 = 7,142.21 : x
2. Step 2: Convert to fraction form
   12,178.86/16,805.98 = 7,142.21/x
3. Step 3: Cross multiply
   12,178.86x = 16,805.98 × 7,142.21
4. Step 4: Simplify right side
   12,178.86x = 120,031,826.34
5. Step 5: Solve for x
   x = 120,031,826.34/12,178.86
6. Step 6: Final answer
   x = 9,855.76