Finding the Fourth Proportional to 31,721.13, 47,534.76 and 12,978.54

Step by Step Solution

1. Step 1: Write the proportion equation
   31,721.13 : 47,534.76 = 12,978.54 : x
2. Step 2: Convert to fraction form
   31,721.13/47,534.76 = 12,978.54/x
3. Step 3: Cross multiply
   31,721.13x = 47,534.76 × 12,978.54
4. Step 4: Simplify right side
   31,721.13x = 616,931,784.05
5. Step 5: Solve for x
   x = 616,931,784.05/31,721.13
6. Step 6: Final answer
   x = 19,448.61