Finding the Fourth Proportional to 12,810.76, 17,678.82 and 7,221.72

Step by Step Solution

1. Step 1: Write the proportion equation
   12,810.76 : 17,678.82 = 7,221.72 : x
2. Step 2: Convert to fraction form
   12,810.76/17,678.82 = 7,221.72/x
3. Step 3: Cross multiply
   12,810.76x = 17,678.82 × 7,221.72
4. Step 4: Simplify right side
   12,810.76x = 127,671,487.97
5. Step 5: Solve for x
   x = 127,671,487.97/12,810.76
6. Step 6: Final answer
   x = 9,965.96