Finding the Fourth Proportional to 12,816.80, 17,684.16 and 7,226.72

Step by Step Solution

1. Step 1: Write the proportion equation
   12,816.80 : 17,684.16 = 7,226.72 : x
2. Step 2: Convert to fraction form
   12,816.80/17,684.16 = 7,226.72/x
3. Step 3: Cross multiply
   12,816.80x = 17,684.16 × 7,226.72
4. Step 4: Simplify right side
   12,816.80x = 127,798,472.76
5. Step 5: Solve for x
   x = 127,798,472.76/12,816.80
6. Step 6: Final answer
   x = 9,971.17