Finding the Fourth Proportional to 12,810.60, 17,678.82 and 7,221.96

Step by Step Solution

1. Step 1: Write the proportion equation
   12,810.60 : 17,678.82 = 7,221.96 : x
2. Step 2: Convert to fraction form
   12,810.60/17,678.82 = 7,221.96/x
3. Step 3: Cross multiply
   12,810.60x = 17,678.82 × 7,221.96
4. Step 4: Simplify right side
   12,810.60x = 127,675,730.89
5. Step 5: Solve for x
   x = 127,675,730.89/12,810.60
6. Step 6: Final answer
   x = 9,966.41