Finding the Fourth Proportional to 31,605.98, 43,610.54 and 20,421.50

Step by Step Solution

1. Step 1: Write the proportion equation
   31,605.98 : 43,610.54 = 20,421.50 : x
2. Step 2: Convert to fraction form
   31,605.98/43,610.54 = 20,421.50/x
3. Step 3: Cross multiply
   31,605.98x = 43,610.54 × 20,421.50
4. Step 4: Simplify right side
   31,605.98x = 890,592,642.61
5. Step 5: Solve for x
   x = 890,592,642.61/31,605.98
6. Step 6: Final answer
   x = 28,177.98