Finding the Fourth Proportional to 12,672.48, 19,012.20 and 5,280.40

Step by Step Solution

1. Step 1: Write the proportion equation
   12,672.48 : 19,012.20 = 5,280.40 : x
2. Step 2: Convert to fraction form
   12,672.48/19,012.20 = 5,280.40/x
3. Step 3: Cross multiply
   12,672.48x = 19,012.20 × 5,280.40
4. Step 4: Simplify right side
   12,672.48x = 100,392,020.88
5. Step 5: Solve for x
   x = 100,392,020.88/12,672.48
6. Step 6: Final answer
   x = 7,922.05