Finding the Fourth Proportional to 12,912.30, 19,336.05 and 10,320.30

Step by Step Solution

1. Step 1: Write the proportion equation
   12,912.30 : 19,336.05 = 10,320.30 : x
2. Step 2: Convert to fraction form
   12,912.30/19,336.05 = 10,320.30/x
3. Step 3: Cross multiply
   12,912.30x = 19,336.05 × 10,320.30
4. Step 4: Simplify right side
   12,912.30x = 199,553,836.82
5. Step 5: Solve for x
   x = 199,553,836.82/12,912.30
6. Step 6: Final answer
   x = 15,454.55