Finding the Fourth Proportional to 12,992.78, 19,488.90 and 5,199.50

Step by Step Solution

1. Step 1: Write the proportion equation
   12,992.78 : 19,488.90 = 5,199.50 : x
2. Step 2: Convert to fraction form
   12,992.78/19,488.90 = 5,199.50/x
3. Step 3: Cross multiply
   12,992.78x = 19,488.90 × 5,199.50
4. Step 4: Simplify right side
   12,992.78x = 101,332,535.55
5. Step 5: Solve for x
   x = 101,332,535.55/12,992.78
6. Step 6: Final answer
   x = 7,799.14