Finding the Fourth Proportional to 12,985.72, 19,478.70 and 5,585.56

Step by Step Solution

1. Step 1: Write the proportion equation
   12,985.72 : 19,478.70 = 5,585.56 : x
2. Step 2: Convert to fraction form
   12,985.72/19,478.70 = 5,585.56/x
3. Step 3: Cross multiply
   12,985.72x = 19,478.70 × 5,585.56
4. Step 4: Simplify right side
   12,985.72x = 108,799,447.57
5. Step 5: Solve for x
   x = 108,799,447.57/12,985.72
6. Step 6: Final answer
   x = 8,378.39