Finding the Fourth Proportional to 21,285.50, 31,900.82 and 19,956.87

Step by Step Solution

1. Step 1: Write the proportion equation
   21,285.50 : 31,900.82 = 19,956.87 : x
2. Step 2: Convert to fraction form
   21,285.50/31,900.82 = 19,956.87/x
3. Step 3: Cross multiply
   21,285.50x = 31,900.82 × 19,956.87
4. Step 4: Simplify right side
   21,285.50x = 636,640,417.85
5. Step 5: Solve for x
   x = 636,640,417.85/21,285.50
6. Step 6: Final answer
   x = 29,909.59