Finding the Fourth Proportional to 12,990.56, 19,488.27 and 4,227.98

Step by Step Solution

1. Step 1: Write the proportion equation
   12,990.56 : 19,488.27 = 4,227.98 : x
2. Step 2: Convert to fraction form
   12,990.56/19,488.27 = 4,227.98/x
3. Step 3: Cross multiply
   12,990.56x = 19,488.27 × 4,227.98
4. Step 4: Simplify right side
   12,990.56x = 82,396,015.79
5. Step 5: Solve for x
   x = 82,396,015.79/12,990.56
6. Step 6: Final answer
   x = 6,342.76