Finding the Fourth Proportional to 12,985.56, 19,478.52 and 5,585.40

Step by Step Solution

1. Step 1: Write the proportion equation
   12,985.56 : 19,478.52 = 5,585.40 : x
2. Step 2: Convert to fraction form
   12,985.56/19,478.52 = 5,585.40/x
3. Step 3: Cross multiply
   12,985.56x = 19,478.52 × 5,585.40
4. Step 4: Simplify right side
   12,985.56x = 108,795,325.61
5. Step 5: Solve for x
   x = 108,795,325.61/12,985.56
6. Step 6: Final answer
   x = 8,378.18