Finding the Fourth Proportional to 31,443.57, 47,152.80 and 12,720.02

Step by Step Solution

1. Step 1: Write the proportion equation
   31,443.57 : 47,152.80 = 12,720.02 : x
2. Step 2: Convert to fraction form
   31,443.57/47,152.80 = 12,720.02/x
3. Step 3: Cross multiply
   31,443.57x = 47,152.80 × 12,720.02
4. Step 4: Simplify right side
   31,443.57x = 599,784,323.29
5. Step 5: Solve for x
   x = 599,784,323.29/31,443.57
6. Step 6: Final answer
   x = 19,074.94