Finding the Fourth Proportional to 21,639, 29,861.82 and 15,362.31

Step by Step Solution

1. Step 1: Write the proportion equation
   21,639 : 29,861.82 = 15,362.31 : x
2. Step 2: Convert to fraction form
   21,639/29,861.82 = 15,362.31/x
3. Step 3: Cross multiply
   21,639x = 29,861.82 × 15,362.31
4. Step 4: Simplify right side
   21,639x = 458,746,536.00
5. Step 5: Solve for x
   x = 458,746,536.00/21,639
6. Step 6: Final answer
   x = 21,199.99