Finding the Fourth Proportional to 31,149.63, 42,973.47 and 20,397.15

Step by Step Solution

1. Step 1: Write the proportion equation
   31,149.63 : 42,973.47 = 20,397.15 : x
2. Step 2: Convert to fraction form
   31,149.63/42,973.47 = 20,397.15/x
3. Step 3: Cross multiply
   31,149.63x = 42,973.47 × 20,397.15
4. Step 4: Simplify right side
   31,149.63x = 876,536,313.61
5. Step 5: Solve for x
   x = 876,536,313.61/31,149.63
6. Step 6: Final answer
   x = 28,139.54