Finding the Fourth Proportional to 12,861.55, 17,748.79 and 7,196.21

Step by Step Solution

1. Step 1: Write the proportion equation
   12,861.55 : 17,748.79 = 7,196.21 : x
2. Step 2: Convert to fraction form
   12,861.55/17,748.79 = 7,196.21/x
3. Step 3: Cross multiply
   12,861.55x = 17,748.79 × 7,196.21
4. Step 4: Simplify right side
   12,861.55x = 127,723,979.91
5. Step 5: Solve for x
   x = 127,723,979.91/12,861.55
6. Step 6: Final answer
   x = 9,930.68