Finding the Fourth Proportional to 12,980.49, 19,420.17 and 9,869.50

Step by Step Solution

1. Step 1: Write the proportion equation
   12,980.49 : 19,420.17 = 9,869.50 : x
2. Step 2: Convert to fraction form
   12,980.49/19,420.17 = 9,869.50/x
3. Step 3: Cross multiply
   12,980.49x = 19,420.17 × 9,869.50
4. Step 4: Simplify right side
   12,980.49x = 191,667,367.82
5. Step 5: Solve for x
   x = 191,667,367.82/12,980.49
6. Step 6: Final answer
   x = 14,765.80