Finding the Fourth Proportional to 12,338.72, 17,021.52 and 7,621.28

Step by Step Solution

1. Step 1: Write the proportion equation
   12,338.72 : 17,021.52 = 7,621.28 : x
2. Step 2: Convert to fraction form
   12,338.72/17,021.52 = 7,621.28/x
3. Step 3: Cross multiply
   12,338.72x = 17,021.52 × 7,621.28
4. Step 4: Simplify right side
   12,338.72x = 129,725,769.95
5. Step 5: Solve for x
   x = 129,725,769.95/12,338.72
6. Step 6: Final answer
   x = 10,513.71